Welcome to the X Chemistry Guess Paper 2026 prepared by Inam Jazbi, your trusted source for quality educational content and exam preparation. This post includes chapter-wise important MCQs, short questions, and long questions carefully selected from past board papers, new syllabus, and model tests to help you score top marks in your upcoming exams.
Whether you’re following the new textbook or revising for your final term, this Chemistry Class 10 Guess Paper 2026 by Inam Jazbi highlights the most expected questions, repeated concepts, and key topics every student must prepare.
💡 What’s Inside:
✅ 100% important MCQs, short & long questions
✅ Based on new paper pattern 2026
✅ Easy and quick revision format
✅ Ideal for board exam preparation
✅ Based on New Syllabus & Board Paper Scheme 2026
✅ Includes Most Repeated MCQs & Short Questions
✅ Prepared by Experienced Teacher
✅ Perfect for Final Term & Board Exams
Start revising today with Inam Jazbi’s trusted Guess Paper 2026 and make your Chemistry exam success guaranteed! Get ready to ace your X Chemistry exam 2026 with these reliable and accurate guess papers — your shortcut to success!
✏️ X-CHEMISTRY Guess Paper 2026 with solution
Dr Inam Ul Haq Jazbi ✏️
✏️ Section-B (Short-Answer Questions) 8 Questions 3 marks each (24) ✏️
(ii) Reversible 🔄 and irreversible reactions ❌
(iii) Saturated 🟢 and unsaturated hydrocarbons 🟠
(iv) Dextrorotary ➡️ and Levorotatory Sugars ⬅️
(v) Quantitative 📈 and qualitative analysis 🔎
(vi) Titrimetric ⚗️ and gravimetric analysis ⚖️
(vii) Classical 📚 and Instrumental Methods 🎛️
(viii) Fat-soluble 🧴 and water-soluble vitamins 💧
(ix) DNA 🧬 and RNA 🧬
(x) Fat 🥓 and oil 🛢️
(xi) Aldoses 🍬 and ketoses 🍭
(xii) Forward ➡️ and reverse reactions ⬅️
OR
What is equilibrium constant? Write down any three characteristics of equilibrium constant. Why equilibrium constant may or may not have unit? Justify with example.
(i) N₂(g) + 2O₂(g) ⇌ 2NO₂(g) ⚗️
(ii) H₂(g) + I₂(g) ⇌ 2HI(g) 🧪
(iii) CO₂(g) + H₂(g) ⇌ CO(g) + H₂O(g) 💧
(iv) 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) 🔥
(v) N₂(g) + 3H₂(g) ⇌ 2NH₃(g) 🌿
(vi) CO(g) + 3H₂(g) ⇌ CH₄(g) + H₂O(g) ⚡
HS⁻, H₃O⁺, H₂PO₄⁻, HSO₄⁻, HF, CH₃COOH, [Al(H₂O)₆]³⁺, OH⁻, HCO₃, HPO₄²⁻, CH₃NH₂, CO₃²⁻
(b) Which of the following behave both as Bronsted acids and Bronsted bases?
H₂O, HCO₃⁻, H₂SO₄, H₃PO₄, HS⁻
OR
What are conjugate acid-base pairs? Also define conjugate acid and conjugate base.
Identify acid, base, conjugate acid and conjugate base in the following reactions:
➡️ CH₃COOH + H₂O ⇌ H₃O⁺ + CHCOO₃⁻
➡️ NH₃ + HCl ⇌ NH₄⁺ + Cl⁻
➡️ H₂O + NH₃ ⇌ NH₄⁺ + OH⁻
OR
Write the names and structural formulae of six carbons alkanes, alkenes, alkyne, cycloalkane and aromatic hydrocarbons.
OR
Draw the structures of following compounds:
(i) 2,3-dimethylpentane
(ii) 3-ethyl-1-hexene
(iii) 2-butyne
(iv) 2,4-hexadiene
(v) 3-methyl-1,4-hexadiyne
(vi) 2-hepten-5-yne
(vii) 2-pentyne
(viii) neopentane
(ix) iso-propyl alcohol
(x) Phenol or toluene
(xi) iso-butane
(xii) Cyclohexane
Ethane, Ethene and Ethyne, ethyl alcohol, acetic acid, acetone, n-butane, isobutane, methyl acetate, dimethyl amine
OR
Define functional group. Identify the functional groups in the following compounds:
(a) CH₃CHO (Aldehydic group)
(b) CH₃CH₂CH₂OH (primary alcoholic group)
(c) CH₃COCH₃ (ketonic carbonyl group)
(d) C₃H₇COOH (carboxylic group)
(e) CH₂=CHCH₃ (double bond)
(f) CH₃OCH₃
(g) CH₃CH₂COOCH₃
Copper sulphate, Calcium sulphate dehydrated, iron sulphate hepta hydrated, sodium hydrogen carbonate, barium sulphate, potassium permangate.
OR
What are enzymes? Write one use of enzymes yeast, cellulase, lipase, lactase and amylase.
OR
What is homologous series? Name the any two common homologous series with examples. Write down the general characteristics of homologous series. Write the possible isomers of Pentane with their common name and IUPAC name.
OR
What is alkyl radicals? Give its type formula and general formula. Explain with structure different radicals of butane. What is the difference of alkyl radicals obtained from propane?
OR
Define buffers. What is the composition of buffers? How are they prepared? Discuss its importance in our daily life.
OR
What are amino acids and peptide bond? How peptide bond is formed? Also explain dipeptides & tripeptides.
OR
Write down three characteristics of organic compounds.
OR
Write down three uses of organic compounds.
(i) Why Silicon compounds are lesser than that of Carbon compounds?
(ii) Why pure water is considered as weak electrolyte?
(iii) Justify the petroleum is ‘black gold’.
(iv) Alkanes are said to be saturated hydrocarbons.
(v) Justify that water soluble vitamins are not injurious to health.
(vi) Justify that greenhouse effect leads to global warming.
(vii) Justify that “water is solvent”.
(viii) How is vegetable oil converted into saturated fat (ghee)?
(ix) Why chemical equilibrium is considered dynamic not static?
(x) Why the temperature on top of a mountain is colder than at sea level?
(xi) Why organic compounds have great diversity in magnitude.
(xii) Why IR spectroscopy is more advantageous than UV-vis spectroscopy? explain.
(i) Ca(OH)₂ + H₂SO₄ → __________ + __________.
(ii) NaOH + H₂SO₄ → __________ + __________.
(iii) NaOH + H₃PO₄ → __________ + __________.
OR
Define vitamin and complete the following chart:
| Vitamin Name | Sources | Deficiency Disease |
| Vitamin A | __________ | __________ |
| Vitamin D | __________ | __________ |
| Vitamin E | __________ | __________ |
| Vitamin K | __________ | __________ |
| Vitamin C | __________ | __________ |
OR
What are the carbohydrates? Explain sources and types of carbohydrates.
OR
What are fatty acids? Give their examples and chemical nature.
OR
Give general formula for Alkanes, Alkenes and Alkynes. Identify Alkanes, alkenes, alkynes, cycloalkanes and aromatics in each of the following:
C₆H₆, C₂H₄, C₃H₄, C₃H₈, C₆H₁₂, C₅H₈, C₄H₆, C₆H₅OH
(i) Diarrheal Diseases
(ii) Dysentery
(iii) Cholera
(iv) Crytosporidium
(v) Fluorosis
(vi) Hepatitis
(vii) Hookworm
(viii) Typhoid
OR
Define atmosphere. Discuss its composition. Write down the names of different atmospheric layers with their altitude and temperatures.
OR
Give difference between primary and secondary air pollutants. Identify as primary or secondary air pollutant: SO₂, CH₄, HNO₃, NH₃, H₂SO₄ and O₃
OR
Define qualitative analysis. What are organic and inorganic qualitative analyses. Give their examples.
OR
Define quantitative analysis. What are the physical and chemical methods of quantitative analysis?
OR
What is vitamin D? Give its sources and importance.
✏️ Section-C (Long-Answer Questions) 4 Questions 6 marks each (24) ✏️
Predict, which system at equilibrium, will contain maximum amount of reactant or maximum amount of product:
(i) 2CO₂ ⇌ 2CO + O₂ Kc = 3.1 ×10⁻¹⁸ mol.dm⁻³
(ii) 2O₃ ⇌ 3O₂ Kc = 5.9 ×10⁵⁵ mol.dm⁻³
Explain with an example that water is a Bronsted-Lowry acid as well as Bronsted-Lowry base.
Give limitations of Bronsted-Lowry theory.
OR
State three different theories about concepts of acids and bases with one example and also indicate one limitation of each concept.
Which of the following is/are Arrhenius acids and bases?
(a) Ca(OH)₂
(b) HNO₃
(c) NaOH
(d) H₂SO₄
(e) KOH
OR
Define nomenclature and describe IUPAC nomenclature rules for alkynes and alkanes. Write down IUPAC names of following:
OR
What do you mean by diversity and magnitude of organic compounds? Give at least 5 reasons.
OR
Give classification of organic compounds and the important characteristic of organic compounds.
OR
What are proteins and peptide bond? How peptide bond is formed in dipeptides and tripeptides? Write down the range of Number of Amino Acids & molecular weights of Proteins. Give importance & sources of proteins.
OR
What are vitamins. Differentiate its two types with their sources. Name the diseases caused by the deficiency of both types of vitamins.
OR
Define Atmosphere. Enlist the layers of atmosphere. Differentiate between troposphere and stratosphere?
OR
What is Titrimetric Analysis? Describe how it is performed with diagram.
OR
Describe global warming. Justify that greenhouse effect leads to global warming.
OR
Describe HPLC in details.
OR
What is spectroscopy? How is it used in the chemical analysis of a substance? Also discuss its types.
OR
Define pollutant. Enlist the names of seven types of pollutants. What are primary and secondary air pollutants? Give the sources, environmental and health risks of the following:
COₓ, SOₓ, NOₓ, lead, ozone
✏️ Numericals ✏️
2NO₍g₎ + O₂₍g₎ ⇌ 2NO₂₍g₎
At equilibrium at 230°C, the concentrations are measured to be:
[NO] = 0.0542 mol dm⁻³, [O₂] = 0.127 mol dm⁻³ and [NO₂] = 15.5 mol dm⁻³
Calculate the equilibrium constant at this temperature. (Book problem 1; page 8)
Answer: 6.44 × 10⁵ mol⁻¹ dm³
Fe³⁺ + 4Cl⁻ ⇌ FeCl₄⁻
At equilibrium the concentrations are measured to be:
Fe³⁺ = 0.2 mol dm⁻³, Cl⁻ = 0.28 mol dm⁻³ and FeCl₄⁻ = 0.95 × 10⁻⁴ mol dm⁻³
Calculate equilibrium constant Kc for given reaction. (Book problem 1; page 9)
Answer: 7.2 × 10⁻² mol⁻⁴ dm¹²
[H₂]ₜ = 0.10 mol dm⁻³, [I₂]ₜ = 0.20 mol dm⁻³, [HI]ₜ = 0.40 mol dm⁻³
Predict in which direction reaction will move to achieve equilibrium.
Answer: Qc (8.0) < Kc (57.0), forward direction
H₂₍g₎ + I₂₍g₎ ⇌ 2HI₍g₎
The equilibrium concentrations are:
[H₂] = 0.05 mol dm⁻³; [I₂] = 0.06 mol dm⁻³; [HI] = 0.49 mol dm⁻³
Calculate the equilibrium constant for this reaction. (Book problem 1; page 9)
Answer: Kc = 80
N₂₍g₎ + 3H₂₍g₎ ⇌ 2NH₃₍g₎ , Kc = 3.0 × 10⁻⁹
The equilibrium concentrations of these gases are: nitrogen 0.602 mol dm⁻³; hydrogen 0.420 mol dm⁻³ and ammonia 0.113 mol dm⁻³.
What is value of Kc?
Answer: 0.286 mol⁻² dm⁶
N₂(g) + O₂(g) ⇌ 2NO(g)
Find the concentration of NO in an equilibrium mixture at 1 atmosphere at 2000°C. In air, [N₂] = 0.036 mol/L and [O₂] = 0.0089 mol/L. (Book problem 3; page 10)
Answer: 3.6 × 10⁻⁴ mol/L
Answer: [OH⁻] = 2.46 × 10⁻⁹ M, [H⁺] = 4.07 × 10⁻⁶ M, pH = 5.39, pOH = 8.61
Answer: pOH = 11.7, [H⁺] = 5.01 × 10⁻³
Answer: pH = 1.7
Answer: [H⁺] = 0.089 M, pOH = 12.95
Answer: pH ≈ 6.98, pOH ≈ 7.02, [OH⁻] ≈ 1.0 × 10⁻⁸ M, [H⁺] ≈ 1.05 × 10⁻⁷ M
✏️ X-CHEMISTRY Interactive MCQs (Click MCQ to reveal answer and reason
Dr Inam Ul Haq Jazbi ✏️
N2 + 3H2 ⇌ 2NH3 ; Kc = 2.86 mol⁻² dm⁶
What will be present in the equilibrium mixture?
✏️ Smart Answers of Section-B (Short-Answer Questions) ✏️
1️⃣ Define any three of the following:
Equilibrium constant, reaction quotient, extent of a reaction, pH, Indicator, Neutralization, Titration, alicyclic compounds, aromatic compounds, catenation, aldoses, ketoses, saccharides, functional group, Peptide linkage, Saponification, lipids, enzymes, isomerism, Bloor’s reagent, fatty acid, ozone hole, organic chemistry, Biochemistry, Environmental chemistry, Analytical Chemistry, Qualitative Analysis, Quantitative Analysis, accuracy, precision, titrant, analyte, Indicator, parameter, homologous series, alkyl radicals, glycosidic linkage, nucleotide, Potentiometry, stationary phase, mobile phase, retention time, active mass, dynamic equilibrium, chromatography.
Answer
🔬 Chemical Equilibrium Terms
⚖️ Active Mass
It is the molar concentration (mol dm⁻³) of a substance taking part in a reaction, represented by [ ].
📊 Equilibrium Constant (Kc)
The equilibrium constant (Kc) of a reversible reaction is the ratio of the product of equilibrium molar concentrations (active masses) of products to that of reactants, each raised to the power of their respective stoichiometric coefficients in the balanced chemical equation, at a constant temperature.
Kc = Kᵳ/Kᵣ = [P]/[R] = [C]ᶜ [D]ᵈ/[A]ᵃ [B]ᵇ
🔁 Dynamic Equilibrium
Dynamic equilibrium is the condition where forward and reverse processes occur continuously at the same rate, so no overall change is observed in the system keeping the system stable.
🧪 Reaction Quotient (Qc)
The reaction quotient (Qc) is the ratio of the concentrations of products to reactants at any point (not necessarily at equilibrium) during a reaction, each raised to the power of their coefficients. It is the same expression as Kc but calculated using initial (non-equilibrium) concentrations.
Qc = [Pᵢ]/[Rᵢ] = [Cᵢ]ᶜ [Dᵢ]ᵈ/[Aᵢ]ᵃ [Bᵢ]ᵇ
📈 Extent of Reaction
It is the measure of how far reactants are converted into products.
🧪 Acids, Bases & Titration
pH 🧫
pH is a measure of acidity or basicity defined as the negative logarithm of the molar hydrogen ions concentration of a solution ranging from 0 to 14. pH = –log[H⁺].
🎨 Indicator
It is a weak organic acid or base that changes colour over a specific pH range to show end-point during titrations.
💧 Neutralization
It is the reaction between an Arrhenius acid and an Arrhenius base to form salt and water.
🧪📐 Titration
It is a method to determine the concentration of an unknown solution (analyte) using a solution of known concentration (titrant).
💉 Titrant
It is the solution of known concentration added during titration.
🧬 Analyte
It is the substance whose concentration is being determined.
🌱 Organic Chemistry Basics
Organic Chemistry 🧪
It is the study of carbon-containing compounds mainly hydrocarbons and their derivatives and their reactions.
Catenation 🔗
It is the ability of carbon to form chains by bonding with itself. It is the self-linking property of carbon.
Functional Group 🧩
It is an atom or group of atoms or multiple bonds that gives characteristic properties to an organic compound. e.g. –OH group is the functional group of alcohol family (R–OH).
Isomerism 🔄
Isomerism is the existence of two or more compounds with same molecular formula but different structures and properties. (This is mainly because of different structural or spatial arrangements.)
Homologous Series 🧬
A family of organic compounds with similar properties and a common functional group, differing by –CH₂.
Alkyl Radical 🌿
A hydrocarbon group formed by removal of one hydrogen atom from an alkane (e.g., –CH₃).
Acyclic (Aliphatic) Compounds 🔓
Open-chain (aliphatic) compounds consist of carbon atoms arranged in open, continuous straight or branched chains (rather than closed cyclic structures), with the terminal (end) carbon atoms not connected to each other. Open-chain compounds are also known as aliphatic compounds. Examples: n-pentane, isopentane, propane, butane.
Alicyclic Compounds 🔵
These are the cyclic or Carbocyclic compounds without benzene rings. Cyclopropane (C₃H₆), Cyclobutane (C₄H₈), Cyclopentane (C₅H₁₀), Cyclohexane (C₆H₁₂) etc.
Aromatic Compounds 🌸
These are the cyclic or Carbocyclic compounds containing one or more benzene rings (six carbon atoms with three alternating double bonds). e.g. benzene and naphthalene.
🍬 Carbohydrates & Biomolecules
Saccharides 🍞
Saccharides commonly known as carbohydrates defined as polyhydroxy aldehydes or ketones or large molecules that give these compounds on hydrolysis..
Aldoses 🍯
The carbohydrates or sugars containing an aldehyde (–CHO) functional group. e.g. Glucose, Ribose
Ketoses 🍬
The carbohydrates or sugars containing a ketonic (>C=O) functional group. e.g. Fructose, Ribulose
Glycosidic Linkage 🔗🍬
The bond linking monosaccharides in carbohydrates.
Nucleotide 🧬
The basic unit of nucleic acids made of sugar, base, and phosphate group.
🧠 Biochemistry & Biological Molecules
Biochemistry 🧬
It is the study of naturally occurring macromolecules and their chemical processes occurring in living organisms.
Enzymes ⚡
Enzymes are the class of proteins which are biocatalysts produced by living cells that speed up biochemical reactions.
Peptide Linkage 🔗
It is the acid-amide (–CO–NH–) bond linking amino acids in proteins by eliminating a water molecule. (A protein molecule formed with two amino acids is termed as dipeptide, with three tripeptide and so son. This linkage is formed by the removal of a water molecule b/w an NH₂ group of an amino acid and COOH group of another).
Lipids 🧈
Lipids are a group of naturally occurring heterogeneous water-insoluble non-polar organic compounds (like fats, oils, and waxes) of the plant and animal origins that are soluble in Bloor’s reagent and organic solvents.
Fatty Acids 🧪
Fatty acids are naturally long-chain aliphatic saturated or unsaturated carboxylic acids that form fats and oils containing even number of carbon atoms (ranges C₁₂-C₂₀). Fatty acids are building blocks of lipids. e.g. Palmitic acid; C₁₅H₃₁COOH, Stearic acid; C₁₇H₃₅COOH
Saponification 🧼
It is the conversion of fats or oils into soap using alkali. It is the reaction of triglycerides or fats or oils with sodium or potassium hydroxide to form glycerol and fatty acid salt called soap.
Bloor’s Reagent 🧴
It is a 2:1 mixture of diethyl ether and ethyl alcohol used to dissolve lipids.
🌍 Environmental Chemistry
Environmental Chemistry 🌎
Environmental Chemistry is the study of chemical and biological processes in air, water, and soil and human impact on them.
Ozone Hole 🕳️☀️
It is the region of severe depletion of ozone layer in the stratosphere.
📊 Analytical Chemistry & Measurement
Analytical Chemistry 🔍
It is the branch of chemistry concerned with separation, identification, and quantification of substances through various techniques and instruments.
Qualitative Analysis 🧾
It involves identification of components of elements, ions or compounds present in a sample focusing only its quality.
Quantitative Analysis ⚖️
It involves determination of the exact amount of substances present.
Accuracy 🎯
It is the closeness of a measured value to the true value of a sample.
Precision 📏
It is the closeness of repeated measurements of the same quantity to each other.
Parameter 🧠
It is a measurable factor used to validate analytical methods (accuracy, precision, linearity, etc.).
🧪 Chromatography & Instrumental Methods
Chromatography 🧫➡️
A separation technique based on different distribution of components between two phases.
Stationary Phase 🧱
The immobile phase in chromatography.
Mobile Phase 🚿
The moving phase that carries the sample.
Retention Time ⏱️
Time taken by a component to pass through the stationary phase.
Potentiometry 🔌
An analytical technique that measures electrode potential to determine concentration.
2️⃣
Write down three differences between any one of the following:
(i) Troposphere and Stratosphere
(ii) Reversible and irreversible reactions
(iii) Saturated and unsaturated hydrocarbons
(iv) Dextrorotary and Levorotatory Sugars
(v) Quantitative analysis and qualitative analysis
(vi) Titrimetric analysis and gravimetric analysis
(vii) Classical and Instrumental Methods
(viii) Fat and water-soluble vitamins
(ix) DNA and RNA
(x) Fat and oil
(xi) Aldoses and ketoses
(xii) Forward and reverse reactions
Answer
(i) 🌿 Saturated vs Unsaturated Hydrocarbons
Contain only C–C single bonds 🔗
Contain C=C or C≡C bonds ⚡
(ii) 🧈 Fat vs Oil
Solid at room temperature ❄️
Liquid at room temperature 🌡️
(iii) 💊 Fat-soluble vs Water-soluble Vitamins
Soluble in fats & oils
Soluble in water
(iv) 🔄 Dextrorotatory vs Levorotatory Sugars
Rotate plane-polarized light right
Rotate plane-polarized light left
(v) 📊 Quantitative vs Qualitative Analysis
Deals with amount of substance 📊
Deals with nature of substance 🔬
(vi) 🔁 Reversible vs Irreversible Reactions
Occur in both forward & reverse directions
Occur in one direction only i.e. forward
(vii) 🧪 Classical vs Instrumental Methods ⚙️
Simple procedures
Sensitive & technical procedures
(viii) 🌍 Troposphere vs Stratosphere
Lowest layer of atmosphere
Layer above the troposphere
3️⃣
Define chemical equilibrium state with its any three macroscopic properties. Why chemical equilibrium is dynamic? Explain it with one example.
Answer
📖 Definition of Chemical Equilibrium
Chemical equilibrium is the state of a reversible reaction carried out in a closed system at which there is no observable change in the concentrations of reactants and products with time, because the rate of forward reaction is equal to the rate of reverse reaction.
At equilibrium:
➡️ Rate of forward reaction = Rate of backward reaction
➡️ Concentrations of reactants and products remain constant
📌 Macroscopic Properties of Chemical Equilibrium (Any three)
🔄 Chemical Equilibrium as Dynamic Equilibrium
Chemical equilibrium is dynamic because both forward and reverse reactions continue to occur at the same rate even after equilibrium is established.
Neither reaction stops; they occur continuously but at equal speed, so there is no net change in concentration.
🧪 Example: Formation of Hydrogen Iodide
H₂ (g) + I₂ (g) ⇌ 2HI (g)
➡️ Initially, the concentrations of H₂ and I₂ are high and HI is zero.
➡️ As the reaction proceeds, H₂ and I₂ decrease, and HI increases.
➡️ As HI accumulates, the reverse reaction starts.
➡️ The rate of forward reaction decreases while the reverse reaction increases.
➡️ Finally, both rates become equal and equilibrium is established.
➡️ Concentrations of H₂, I₂ and HI remain constant, though reactions continue.
OR
What is equilibrium constant? Write down any three characteristics of equilibrium constant. Why equilibrium constant may or may not have unit? Justify with example.
Answer
📖 Definition of Equilibrium Constant
The equilibrium constant (Kc) of a reversible reaction is the ratio of the product of equilibrium molar concentrations (active masses) of products to that of reactants, each raised to the power of their respective stoichiometric coefficients, at a constant temperature.
🧮 Mathematical Expression of Kc
For a general reversible reaction: aA + bB ⇌ cC + dD
Kc = [C]ᶜ [D]ᵈ / [A]ᵃ [B]ᵇ
⭐ Characteristics of Equilibrium Constant
📌 Importance of Kc
➡️ Helps predict extent of reaction.
➡️ Indicates position of equilibrium.
➡️ Useful in industrial and chemical calculations.
📐 Unit of Equilibrium Constant (Kc)
When the number of moles of gaseous reactants equals the number of moles of gaseous products, concentration units cancel out.
Example: CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g) → Kc has no unit.
When the number of moles of reactants and products are not equal, Kc has a unit.
Example: N₂(g) + 3H₂(g) ⇌ 2NH₃(g)
Reactants = 4 moles, Products = 2 moles
Kc = [NH₃]² / [N₂][H₂]³ = 1/[mol.dm⁻³]² → mol⁻² dm⁶
4️⃣
Write down Equilibrium Constant Expression (Kc) and unit of Kc for any 3 of the following balanced reversible reactions.
(i) N₂₍g₎ + 2O₂₍g₎ ⇌ 2NO₂₍g₎ (ii) H₂₍g₎ + I₂₍g₎ ⇌ 2HI₍g₎
(iii) CO₂₍g₎ + H₂₍g₎ ⇌ CO₍g₎ + H₂O₍g₎ (iv) 2SO₂₍g₎ + O₂₍g₎ ⇌ 2SO₃₍g₎
(v) N₂₍g₎ + 3H₂₍g₎ ⇌ 2NH₃₍g₎ (vi) CO₍g₎ + 3H₂₍g₎ ⇌ CH₄₍g₎ + H₂O₍g₎
Answer
5️⃣
(a) What are conjugate acids and conjugate bases of each of the following?
HS⁻, H₃O⁺, H₂PO₄⁻, HSO₄⁻, HF, CH₃COOH, [Al(H₂O)₆]³⁺, OH⁻, HCO₃⁻, HPO₄²⁻, CH₃NH₂, CO₃²⁻
(b) Which of the following behave both as Bronsted acids and Bronsted bases?
H₂O, HCO₃⁻, H₂SO₄, H₃PO₄, HS⁻
Answer
🧪 5(a) Conjugate Acids and Conjugate Bases
Rule reminder 🔁
Conjugate acid → formed by adding H⁺
Conjugate base → formed by removing H⁺
⚡ HS⁻ ➡ Conjugate acid: H₂S ➕ ➡ Conjugate base: S²⁻ ➖
⚡ H₃O⁺ ➡ Conjugate acid: H₄O²⁺ ➕ ➡ Conjugate base: H₂O ➖
⚡ H₂PO₄⁻ ➡ Conjugate acid: H₃PO₄ ➕ ➡ Conjugate base: HPO₄²⁻ ➖
⚡ HSO₄⁻ ➡ Conjugate acid: H₂SO₄ ➕ ➡ Conjugate base: SO₄²⁻ ➖
⚡ HF ➡ Conjugate acid: H₂F⁺ ➕ ➡ Conjugate base: F⁻ ➖
⚡ CH₃COOH ➡ Conjugate acid: CH₃COOH₂⁺ ➕ ➡ Conjugate base: CH₃COO⁻ ➖
⚡ [Al(H₂O)₆]³⁺ ➡ Conjugate acid: [Al(H₂O)₆]⁴⁺ ➕ ➡ Conjugate base: [Al(H₂O)₅OH]²⁺ ➖
⚡ OH⁻ ➡ Conjugate acid: H₂O ➕ ➡ Conjugate base: O²⁻ ➖
⚡ HCO₃⁻ ➡ Conjugate acid: H₂CO₃ ➕ ➡ Conjugate base: CO₃²⁻ ➖
⚡ HPO₄²⁻ ➡ Conjugate acid: H₂PO₄⁻ ➕ ➡ Conjugate base: PO₄³⁻ ➖
⚡ CH₃NH₂ ➡ Conjugate acid: CH₃NH₃⁺ ➕ ➡ Conjugate base: CH₃NH⁻ ➖
⚡ CO₃²⁻ ➡ Conjugate acid: HCO₃⁻ ➕ ➡ Conjugate base: CO₃³⁻ ➖
🔄 5(b) Substances Acting as Both Brønsted Acid & Base (Amphoteric)
Amphoteric: H₂O 💧, HCO₃⁻ 🔁, HS⁻ ⚖️
Not amphoteric: H₂SO₄, H₃PO₄ ❌
OR
What are conjugate acid-base pairs? Also define conjugate acid and conjugate base. Identify acid, base, conjugate acid and conjugate base in the following reactions:
➡️ CH₃COOH + H₂O ⇌ H₃O⁺ + CH₃COO⁻
➡️ NH₃ + HCl ⇌ NH₄⁺ + Cl⁻
➡️ H₂O + NH₃ ⇌ NH₄⁺ + OH⁻
Answer
🔁 Conjugate Acid–Base Pairs: A conjugate acid–base pair consists of two species that differ by one proton (H⁺).
🛡️ Conjugate Acid: A conjugate acid is the species formed when a base accepts a proton (H⁺). ➕
📉 Conjugate Base: A conjugate base is the species formed when an acid donates a proton (H⁺). ➖
🧪 Identification in Given Reactions
(i) CH₃COOH (Acid 🍋) + H₂O (Base 💧) ⇌ H₃O⁺ (Conjugate acid) + CH₃COO⁻ (Conjugate base)
➡️ Conjugate pairs: CH₃COOH / CH₃COO⁻, H₂O / H₃O⁺
(ii) NH₃ (Base 🧪) + HCl (Acid 🍋) ⇌ NH₄⁺ (Conjugate acid) + Cl⁻ (Conjugate base)
➡️ Conjugate pairs: HCl / Cl⁻, NH₃ / NH₄⁺
(iii) H₂O (Acid 🍋) + NH₃ (Base 🧪) ⇌ NH₄⁺ (Conjugate acid) + OH⁻ (Conjugate base)
➡️ Conjugate pairs: H₂O / OH⁻, NH₃ / NH₄⁺
6️⃣
State vital force theory and how was this theory discarded by Wohler?
Answer
✨ Vital Force Theory ⚡
Proposed by Jacob Berzelius (1828) 🧪
Claimed organic compounds can only be made by living organisms under a “vital force” 🌱
Cannot be synthesized from inorganic substances ❌
✨ Disproof by Wohler ✅
In 1828, Friedrich Wöhler synthesized urea from ammonium cyanate in the lab 🏭
Showed organic compounds can be made artificially, discarding the theory 🌟
NH₄OCN (ammonium cyanate) — H₂O/Heat (Rearrangement) → (NH₂)₂CO (urea/carbamide)
OR
Write the names and structural formulae of six carbons alkanes, alkenes, alkyne, cycloalkane and aromatic hydrocarbons.
Answer
1️⃣ Alkane (C₆H₁₄) – Hexane ➡️ CH₃–CH₂–CH₂–CH₂–CH₂–CH₃
2️⃣ Alkene (C₆H₁₂) – Hex-1-ene ➡️ CH₂=CH–CH₂–CH₂–CH₂–CH₃
3️⃣ Alkyne (C₆H₁₀) – Hex-1-yne ➡️ CH≡C–CH₂–CH₂–CH₂–CH₃
4️⃣ Cycloalkane (C₆H₁₂) – Cyclohexane ➡️ (CH₂)₆ (ring)
5️⃣ Aromatic (C₆H₆) – Benzene ➡️ ⬡ (hexagonal ring with alternating double bonds)
OR
Draw the structures of following compounds:
Answer
(i) 2,3-Dimethylpentane ➡️ CH₃–CH(CH₃)–CH(CH₃)–CH₂–CH₃
(ii) 3-Ethyl-1-hexene ➡️ CH₂=CH–CH(C₂H₅)–CH₂–CH₂–CH₃
(iii) 2-Butyne ➡️ CH₃–C≡C–CH₃
(iv) 2,4-Hexadiene ➡️ CH₂=CH–CH=CH–CH₂–CH₃
(v) 3-Methyl-1,4-hexadiyne ➡️ CH≡C–CH(CH₃)–CH₂–C≡CH
(vi) 2-Hepten-5-yne ➡️ CH₃–CH=CH–CH₂–C≡C–CH₃
(vii) 2-Pentyne ➡️ CH₃–C≡C–CH₂–CH₃
(viii) Neopentane (2,2-dimethylpropane) ➡️ (CH₃)₄C
(ix) Iso-propyl alcohol ➡️ CH₃–CH(OH)–CH₃
(x) Phenol ➡️ C₆H₅–OH
(x) Toluene ➡️ C₆H₅–CH₃
(xi) Iso-butane (2-methylpropane) ➡️ (CH₃)₂CH–CH₃
(xii) Cyclohexane ➡️ (CH₂)₆ (ring)
7️⃣
Define structural formula. Write down the molecular, structural and condensed formulae of the following compounds:
Ethane, Ethene and Ethyne, ethyl alcohol, acetic acid, acetone, n-butane, isobutane, methyl acetate, dimethyl amine
Answer
📐 Definition of Structural Formula
A structural formula shows the arrangement of atoms and the bonds between them in a molecule.
1️⃣ Ethane
Molecular formula: C₂H₆
Structural formula: H–C–C–H (each C bonded to 3 H)
Condensed formula: CH₃–CH₃
2️⃣ Ethene
Molecular formula: C₂H₄
Structural formula: H₂C=CH₂
Condensed formula: CH₂=CH₂
3️⃣ Ethyne
Molecular formula: C₂H₂
Structural formula: HC≡CH
Condensed formula: HC≡CH
4️⃣ Ethyl alcohol
Molecular formula: C₂H₆O
Structural formula: H–C–C–OH (H₃C–CH₂–OH)
Condensed formula: CH₃–CH₂–OH
5️⃣ Acetic acid
Molecular formula: C₂H₄O₂
Structural formula: H–C–C(=O)–OH
Condensed formula: CH₃–COOH
6️⃣ Acetone
Molecular formula: C₃H₆O
Structural formula: H₃C–C(=O)–CH₃
Condensed formula: (CH₃)₂CO
7️⃣ n-Butane
Molecular formula: C₄H₁₀
Structural formula: CH₃–CH₂–CH₂–CH₃
Condensed formula: CH₃–CH₂–CH₂–CH₃
8️⃣ Isobutane
Molecular formula: C₄H₁₀
Structural formula: (CH₃)₃CH
Condensed formula: (CH₃)₃CH
9️⃣ Methyl acetate
Molecular formula: C₃H₆O₂
Structural formula: CH₃–COO–CH₃
Condensed formula: CH₃–COOCH₃
🔟 Dimethyl amine
Molecular formula: C₂H₇N
Structural formula: (CH₃)₂NH
Condensed formula: (CH₃)₂NH
OR
Define functional group. Identify the functional groups in the following compounds:
Answer
🧩 Functional Group
An atom or group of atoms or multiple bonds in an organic molecule responsible for its characteristic chemical reactions.
Compounds and their Functional Groups
(a) CH₃CHO – Aldehydic group –CHO 📝
(b) CH₃CH₂CH₂OH – Primary alcoholic group –OH 🍹
(c) CH₃COCH₃ – Ketonic carbonyl group –C=O ⚡
(d) C₃H₇COOH – Carboxylic acid –COOH 🧪
(e) CH₂=CHCH₃ – Double bond C=C 🔗
(f) CH₃OCH₃ – Ether –O– 🌬️
(g) CH₃CH₂COOCH₃ – Ester –COO– 🌸
8️⃣
Define salt and its three types with two examples each. Give three uses of salts. Also write any three methods of preparation of salts with equation. Write down any one use of the following salts:
Copper sulphate, Calcium sulphate dehydrated, iron sulphate hepta hydrated, sodium hydrogen carbonate, barium sulphate, potassium permangate.
Answer
🧂 Salt – Definition
A salt is an ionic crystalline compound formed by the neutralization of an acid and a base, consisting of a cation from the base (other than H⁺) and an anion from the acid (other than OH⁻).
Examples: NaCl, CuCl₂
🔖 Three Types of Salts
➡️ Normal Salts ⚖️ – Complete neutralization of acid and base. Examples: NaCl, KNO₃, K₃PO₄
➡️ Acidic Salts 🧪 – Partial neutralization of an acid. Examples: NaHCO₃, NaHSO₄, (NH₄Cl!)
➡️ Basic Salts 🧼 – Partial neutralization of a base. Examples: Mg(OH)Cl, (K₂CO₃!)
Uses of Salts
➡️ NH₄Cl, KCl
➡️ Pesticides 🐞 – e.g., copper(II) sulphate (CuSO₄), iron(II) sulphate (FeSO₄)
➡️ Medicines 💊 – FeSO₄·7H₂O (‘iron pills’) treats anemia
➡️ NaHCO₃ – Antacid to neutralize stomach acid 🧴
➡️ Potassium permanganate (KMnO₄) – Disinfectant to kill bacteria 🧼
➡️ CaSO₄·2H₂O – Plaster of Paris 🏥
➡️ BaSO₄ – X-ray contrast agent in barium meals 🩻
⚗️ Methods of Salt Preparation
Salts are prepared by the action of acids on metals, metal hydroxide (bases or alkalis), metal oxides, metal carbonates and metal bicarbonates. Salts are produced by the action of a base on a metal.
➡️ Acid + Metal → Salt + H₂
2HCl + Mg → MgCl₂ + H₂↑
➡️ Acid + Base → Salt + Water
HNO₃ + KOH → KNO₃ + H₂O
H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O
➡️ Acid + Metal Oxide → Salt + Water
H₂SO₄ + CaO → CaSO₄ + H₂O
➡️ Acid + Carbonate → Salt + Water + CO₂
2HNO₃ + BaCO₃ → Ba(NO₃)₂ + H₂O + CO₂↑
Uses of Specific Salts
➡️ CuSO₄ – Fungicide/pesticide 🐛
➡️ CaSO₄ (dehydrated) – Plaster of Paris 🏥
➡️ FeSO₄·7H₂O – Treats anemia 💊
➡️ NaHCO₃ – Antacid 🧴
➡️ BaSO₄ – X-ray contrast agent 🩻
➡️ KMnO₄ – Disinfectant 🧼
OR
What are enzymes? Write one use of enzymes yeast, cellulase, lipase, lactase and amylase.
Answer
(i) Yeast is used in the fermentation of molasses and starch to make alcohol (Ethanol). 🍞
(ii) Cellulase is used in detergents to break down cellulose into water-soluble glucose 🧼
(iii) Amylase is used as a sweetener in cuisine as well as in the baking of bread 🍪
🧬 Enzymes
Enzymes are biological catalysts that speed up chemical reactions without being consumed.
Uses of Specific Enzymes
➡️ Yeast 🍞 – Ferments molasses or starch (sugars) to produce ethanol (alcohol)
➡️ Cellulase 🧼 – Breaks down cellulose into glucose; used in detergents
➡️ Amylase 🍪 – Converts starch into sugar; used in sweeteners and baking
➡️ Lipase 🥛 – Breaks down fats; used in detergents, cheese, and biodiesel
➡️ Lactase 🥛 – Breaks down lactose; used in lactose-free dairy products and supplements
OR
What is homologous series? Name the any two common homologous series with examples. Write down the general characteristics of homologous series. Write the possible isomers of Pentane with their common name and IUPAC name.
Answer
🧩 Homologous Series
A homologous series (Greek, homo means same and logous means ratio) is a family of similar organic compounds with the same functional group and similar chemical properties, where each successive member differs by methylene (–CH₂) group (14 amu by molecular mass). Each member is called a homologue.
🌟 Examples
Alkanes: Methane (CH₄), Ethane (C₂H₆), Propane (C₃H₈) ➡️ CₙH₂ₙ₊₂
Alkenes: Ethene (C₂H₄), Propene (C₃H₆) ➡️ CₙH₂ₙ
Alkynes: Ethyne (C₂H₂), Propyne (C₃H₄), Butyne (C₄H₆) ➡️ CₙH₂ₙ₋₂
Alkyl halides: Methyl halide (CH₃Cl), Ethyl halide (C₂H₅Cl) ➡️ CₙH₂ₙ₊₁X
Alcohols: Methyl alcohol (CH₃OH), Ethyl alcohol (C₂H₅OH) ➡️ CₙH₂ₙ₊₁OH
🔹 General Characteristics
➕ Successive members differ by –CH₂– (14 u)
🧮 General molecular formula: Alkanes: CₙH₂ₙ₊₂, Alkenes: CₙH₂ₙ, Alkynes: CₙH₂ₙ₋₂
⚗️ General method of preparation: Similar method for all members (e.g., reduction of alkyl halides for alkanes)
🔥 Identical chemical properties: Similar reactivity due to same functional group (e.g., alkanes → combustion, halogenation)
🧬 Isomers of Pentane
🧪 Pentane
📛 Common Name: n-Pentane 🧾 IUPAC Name: Pentane 🔗 Structure: CH₃–CH₂–CH₂–CH₂–CH₃
🧪 Isopentane
📛 Common Name: Isopentane 🧾 IUPAC Name: 2-Methylbutane 🔗 Structure: CH₃–CH(CH₃)–CH₂–CH₃
🧪 Neopentane
📛 Common Name: Neopentane 🧾 IUPAC Name: 2,2-Dimethylpropane 🔗 Structure: (CH₃)₄C
OR
What is alkyl radicals? Give its type formula and general formula. Explain with structure different radicals of butane. What is the difference of alkyl radicals obtained from propane?
Answer
🧬 Alkyl Radicals
Definition: Radicals obtained from alkanes by removing one hydrogen atom are called alkyl radicals or groups.
General symbol: R–
General formula: CₙH₂ₙ₊₁
Origin: R–H — –H → R– e.g. CH₄ — –H → CH₃
🔗 Butyl Radicals (from Butane, C₄H₁₀)
Formula: C₄H₉–
Total isomers: 4 (2 from n-butane + 2 from iso-butane)
From n-butane (CH₃–CH₂–CH₂–CH₃):
➡️ n-Butyl (1°) – H removed from terminal carbon → CH₃–CH₂–CH₂–CH₂–
➡️ sec-Butyl (2°) – H removed from central carbon → CH₃–CH–CH₂–CH₃
From iso-butane ((CH₃)₃CH):
➡️ iso-Butyl (1°) – H removed from terminal carbon → (CH₃)₂CH–CH₂–
➡️ tert-Butyl (3°) – H removed from central carbon → (CH₃)₃C–
🔄 Difference of Alkyl Radicals from Propane vs Butane
Propane gives 2 isomeric propyl radicals (C₃H₇–): n-propyl (1°) and isopropyl (2°).
➡️ n-Propyl (1°) – H removed from terminal carbon → CH₃–CH₂–CH₂–
➡️ Isopropyl (2°) – H removed from central carbon → CH₃–CH–(CH₃)–
Butane gives 4 isomers: n-butyl (1°), sec-butyl (2°), iso-butyl (1°), tert-butyl (3°).
9️⃣
Elaborate ionization equation of water. Explain in detail that how water ionization is related with pH of solution? Also define pH, pOH and neutralization. Prove pH + pOH = 14.
Answer
💧 Ionization of Water
Water is a neutral liquid with equal numbers of H⁺ and OH⁻ ions.
Water is a weak electrolyte because it ionizes slightly in a process called auto-ionization or self-ionization.
Ionization equation: H₂O ⇌ H⁺ + OH⁻ (auto-ionization equilibrium)
⚗️ Equilibrium constant (Kc) for auto-ionization of water:
Kc = [H⁺][OH⁻]/[H₂O]
Kc·[H₂O] = [H⁺][OH⁻] (∵ [H₂O] = constant)
Kw = [H⁺][OH⁻] = 1 × 10⁻¹⁴ mol² dm⁻⁶ at 25°C
⚖️ Neutral solution: [H⁺] = [OH⁻] = 1×10⁻⁷ M (for pure water at 25°C)
🍋 Acidic solution: [H⁺] > [OH⁻]
🧼 Basic solution: [H⁺] < [OH⁻]
📏 pH and pOH
pH: Negative logarithm of hydrogen ion concentration. pH = −log[H⁺]
pOH: Negative logarithm of hydroxide ion concentration. pOH = −log[OH⁻]
🔗 Relation between pH and pOH:
[H⁺][OH⁻] = Kw = 1 × 10⁻¹⁴
log[H⁺] + log[OH⁻] = log(1×10⁻¹⁴)
−log[H⁺] − log[OH⁻] = 14
✅ pH + pOH = 14
⚖️ Neutralization
Definition: Reaction between an acid and a base to form a salt and water.
Example: HCl + NaOH → NaCl + H₂O
OR
Define buffers. What is the composition of buffers? How are they prepared? Discuss its importance in our daily life.
Answer
🧪 Buffer Solution
A buffer is an aqueous solution that resists changes in pH upon addition of small amounts of acid or base.
It maintains a relatively stable pH and neutralizes added H⁺ or OH⁻ ions.
Factor: pH of a buffer is independent of ionic strength but depends on temperature.
Composition: A weak acid + its salt (conjugate base) or weak base + its salt (conjugate acid).
🧩 Types of Buffers / Composition
🍋 Acidic Buffer – Made from weak acid + its salt with strong base (conjugate base). Example: CH₃COOH + CH₃COONa
🧼 Basic Buffer – Made from weak base + its salt with strong acid (conjugate acid). Example: NH₃ + NH₄Cl
⚗️ Preparation of Buffers
Acidic buffer: Mix weak acid with its sodium/potassium salt in water.
Basic buffer: Mix weak base with its salt of strong acid in water.
🌟 Importance of Buffers
❤️ Blood pH maintenance – carbonate, phosphate, protein buffers
🔬 Laboratory reactions – maintain stable pH for experiments
🏭 Industries – leather tanning, sugar, paper, pharmaceuticals
🧫 Biological media – culture media for bacteria & viruses
🌾 Agriculture – improve crop yield
🍎 Food preservation – fruits, canned foods
🧬 Scientific research – molecular biology, microbiology, cell biology, soil science, clinical analysis
🔟
Write any three significant uses of Carbohydrates and lipids.
Answer
🌾 Uses of Carbohydrates
1️⃣ Energy Source ⚡ – Main source of energy for plants and animals.
2️⃣ Structural Support 🌱 – Provide structural support in plants.
3️⃣ Energy Storage 🔋 – Stored as starch (plants) and glucose/glycogen (animals).
🧈 Uses of Lipids
1️⃣ Nutrient Transport 🚚 – Carry fatty acids and vitamins A, D, E, K.
2️⃣ Enzyme Regulation ⚙️ – Help in activation and functioning of enzymes.
3️⃣ Cooking & Frying 🍳🔥 – Fats and oils are commonly used to cook and fry food, improving taste and texture.
OR
What are amino acids and peptide bond? How peptide bond is formed? Also explain dipeptides & tripeptides.
Answer
🧬 Amino Acids
Amino acids are the building blocks of proteins. They are bifunctional organic compounds containing an acidic carboxyl group (–COOH), a basic amino group (–NH₂), and a variable side chain (R) that differs for each amino acid.
✨ Composition:
🧪 Acidic –COOH group
🔬 Basic –NH₂ group
🌟 Unique side chain ‘R’
Structure: R–CH–(NH₂)–COOH
🔗 Peptide Bond
A peptide bond is an acid-amide linkage formed between amino acids with the loss of water, leading to protein formation on polymerization.
⚡ Formation of Peptide Bond:
Amino acid 1 –COOH + Amino acid 2 –NH₂ → Dipeptide + H₂O 💧
NH₂–CH(R)–COOH + H–NH–CH(R)–COOH – H₂O → NH₂–CH(R)–CO–NH–CH(R)–COOH
👯♂️ Dipeptides & Tripeptides
🧩 Dipeptide – protein with 2 amino acids
🧩🧩🧩 Tripeptide – protein with 3 amino acids
OR
Write down three characteristics of organic compounds.
Answer
🧬 Contain Carbon and Hydrogen – Most organic compounds are carbon-based and may also contain O, N, S, or halogens.
🔗 Covalent Bonding – Atoms are joined mainly by covalent bonds, not ionic bonds.
🔥 Low Melting & Boiling Points – Many are volatile and flammable due to weak intermolecular forces.
OR
Write down three uses of organic compounds.
Answer
🌿 Uses of Organic Compounds
🔥 Fuel – e.g., petrol, diesel, natural gas provide energy.
💊 Medicines – e.g., aspirin, antibiotics, vitamins.
🧵 Materials & Polymers – e.g., plastics, synthetic fibers, rubber.
1️⃣1️⃣
Give reason:
(i) Why Silicon compounds are lesser than that of Carbon compounds?
(ii) Why pure water is considered as weak electrolyte?
(iii) Justify the petroleum is ‘black gold’.
(iv) Alkanes are said to be saturated hydrocarbons.
(v) Justify that water soluble vitamins are not injurious to health.
(vi) Justify that greenhouse effect leads to global warming.
(vii) Justify that “water is solvent”.
(viii) How is vegetable oil converted into saturated fat (ghee)?
(ix) Why chemical equilibrium is considered dynamic not static?
(x) Why the temperature on top of a mountain is colder than at sea level?
(xi) Why organic compounds have great diversity in magnitude.
(xii) Why IR spectroscopy is more advantageous than UV-vis spectroscopy? Explain.
Answer
(i) Why Silicon compounds are lesser than Carbon compounds? 🪨
👉 Silicon forms fewer compounds because Si–Si bonds are weaker (200 kJ mol⁻¹) than C–C bonds (355 kJ mol⁻¹) and catenation is less than carbon. 🔗
(ii) Why pure water is considered a weak electrolyte? 💧
👉 Water ionizes slightly to form H⁺ and OH⁻ ions on auto-ionization due to strong hydrogen bonding. ⚡
(iii) Justify petroleum is ‘black gold’ 🛢️
👉 Crude oil is black, but refined products are valuable like gold due to fuels and chemicals. 💰
(iv) Why alkanes are saturated hydrocarbons? 🔥
👉 They have only C–C single bonds and max H atoms with complete saturation of carbon valencies, no addition possible. ✅
(v) Why water-soluble vitamins are not injurious? 🥤
👉 They dissolve in water and are excreted from the body, so excess is non-toxic. 🚽
(vi) Why greenhouse effect leads to global warming? 🌡️
👉 The greenhouse effect or quantity of CO₂ in the air has a direct relationship with global warming effect. CO₂ traps heat in the atmosphere, raising Earth’s average temperature. 🌍
(vii) Why water is a solvent? 💦
👉 Water is polar with ability to form hydrogen bonding (solvating tendency), dissolving many ionic and polar compounds. ⚗️
(viii) How vegetable oil is converted into ghee? 🧈
👉 Hydrogenation converts unsaturated vegetable oils into saturated fats by adding H₂ at 250–300°C in the presence of Ni or Pd catalyst. This is an addition reaction of oil with H₂ to form an adduct called fat.
Hydrogenation: Vegetable oil + H₂ — Ni/Pd catalyst/250–300°C → saturated fat (ghee). 🔥
(ix) Why chemical equilibrium is dynamic, not static? ⚖️
👉 At equilibrium, forward and reverse reactions occur continuously at equal rates with no net change, so the system appears constant but is actually dynamic. 🔄
(x) Why temperature on mountains is colder than sea level? 🏔️
👉 At higher altitudes, lower air pressure causes expansion and reduces heat retention leading to cooling of air, making mountains colder than sea level. ❄️
(xi) Why organic compounds have great diversity? 🌿
👉 Organic compounds are highly diverse due to carbon’s catenation, tetravalency, and ability to form multiple bonds and functional groups. 🔗
(xii) Why IR spectroscopy is more advantageous than UV-vis? 🔬
👉 IR identifies functional groups, while UV-vis only detects conjugated systems; IR is more specific for structure. IR spectroscopy is more useful than UV-Vis because it clearly identifies functional groups and helps in detailed structural analysis. 🧪
1️⃣2️⃣
Complete the following neutralization reactions between acids and bases.
Answer
⚖️ Neutralization Reactions
(i) Ca(OH)₂ + H₂SO₄ → CaSO₄ + 2H₂O
(ii) 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O
(iii) 3NaOH + H₃PO₄ → Na₃PO₄ + 3H₂O
OR
Define vitamin and complete the following chart.
Answer
🍎 Vitamin
A vitamin is an organic compound required in small amounts by the body for normal growth, development, and metabolism, which cannot be synthesized in sufficient quantity by the body and must be obtained from the diet.
🍊🥦 Vitamins Sources and Deficiency Diseases
| 🍏 Vitamin Name | 🌱 Sources | ⚠️ Deficiency Disease |
| Vitamin A 🥕👁️ | Butter, fish, eggs, milk, cheese, green & yellow vegetables, carrots, liver | Night blindness, xerophthalmia, dryness of skin |
| Vitamin D ☀️🦴 | Fish liver, dairy products, mushrooms, oils/fats, formed in skin by sunlight | Rickets |
| Vitamin E 🥜🌿 | Plant oils (wheat germ, cotton seed, corn germ, soybean, peanut), green leafy vegetables | Sterility, haemolysis |
| Vitamin K 🥬🩸 | Green vegetables (spinach, alfalfa, cabbage), cereals | Haemorrhage |
| Vitamin C 🍊🛡️ | Oranges, lemons, tomatoes, green peppers | Scurvy |
1️⃣3️⃣
What are Oligosaccharides, Disaccharides and Polysaccharides. Give their examples and sources.
Answer
🍞🥔 Carbohydrates: Oligosaccharides, Disaccharides & Polysaccharides
1️⃣ Oligosaccharides (Oligo = few)
Definition: Carbohydrates that give 2–10 monosaccharide units on hydrolysis, linked by glycosidic bonds.
Properties: White, crystalline, sweet, water-soluble; may be reducing or non-reducing.
Types: Disaccharides, trisaccharides, tetrasaccharides, etc.
2️⃣ Disaccharides
Definition: Oligosaccharides with 2 monosaccharide units.
Hydrolysis: Produces two monosaccharides (e.g., sucrose → glucose + fructose).
Examples: Sucrose, maltose, lactose (milk sugar).
Sources: Sugarcane, sugar beet, milk, cereals.
3️⃣ Polysaccharides (Poly = many)
Definition: Macromolecular carbohydrates giving >10 monosaccharides on hydrolysis; made of hundreds–thousands of units linked by glycosidic bonds.
Properties: Amorphous, tasteless, insoluble in water, generally non-reducing.
Examples & Sources:
🌿 Cellulose: Plant cell walls, wood, cotton, paper; cotton ~95% cellulose.
🌾 Starch: Cereals (wheat, rice, barley), potato roots.
🐄 Glycogen: Animal starch in muscles & liver.
🍚 Amylose: Component of starch.
OR
What are the carbohydrates? Explain sources and types of carbohydrates.
Answer
🍞🍚 Carbohydrates
Definition: Carbohydrates are organic compounds containing C, H, O in ratio of 2:1 (like H₂O) and are polyhydroxy aldehydes or ketones, or compounds giving these on hydrolysis.
General formula: Cₙ(H₂O)ₙ
🔹 Types of Carbohydrates (Based on Hydrolysis)
1️⃣ Monosaccharides (Mono = one)
Definition: Simplest sugars that cannot be hydrolyzed further.
Hydrolysis: Non-hydrolyzable.
Carbon atoms: 3–10 (trioses, tetroses, pentoses, hexoses, etc.)
Properties: White, crystalline, sweet, water-soluble, reducing sugars.
Examples:
⚡ Glucose (C₆H₁₂O₆): Aldohexose, found in grapes, honey, cane sugar; blood sugar; rapid energy source.
⚡ Fructose (C₆H₁₂O₆): Ketohexose, found in fruits, honey, cane sugar.
2️⃣ Oligosaccharides (Oligo = few)
Definition: Carbohydrates giving 2–10 monosaccharides on hydrolysis, linked by glycosidic bonds.
Properties: White, crystalline, sweet, water-soluble; may be reducing or non-reducing.
Types: Disaccharides, trisaccharides, tetrasaccharides, etc.
2️⃣ Disaccharides
Definition: Oligosaccharides with 2 monosaccharide units.
Hydrolysis: Produces two monosaccharides (e.g., sucrose → glucose + fructose).
Examples: Sucrose, maltose, lactose.
Sources: Sugarcane, sugar beet, milk, cereals.
3️⃣ Polysaccharides (Poly = many)
Definition: Macromolecular carbohydrates giving >10 monosaccharides on hydrolysis.
Properties: Amorphous, tasteless, insoluble in water, generally non-reducing.
Examples & Sources:
🌿 Cellulose: Plant cell walls, cotton.
🌾 Starch: Cereals (wheat, barley), potato.
🐄 Glycogen: Liver & muscles.
🍚 Amylose: Component of starch.
🌱 Sources of Carbohydrates
📌 Monosaccharides 🍇🍯 – Glucose, Fructose: Grapes, honey, molasses, guava
📌 Oligosaccharides 🍬 – Sucrose: Sugarcane, beetroot, carrots, pineapple; Lactose: Milk 🥛; Maltose: Wheat 🌾, barley 🌾; Raffinose: Legumes
📌 Polysaccharides 🌿 – Cellulose: Plant cell walls, cotton 🏵️; Starch: Cereals, potato 🥔; Glycogen: Liver & muscles 🐄
1️⃣4️⃣
What are amino acids and give their general structure? How many Essential and Non-essential Amino Acids are there? Write down the range of Number of Amino Acids and molecular weights of Proteins.
Answer
🧬 Definition of Amino Acids
Amino acids are the building blocks of proteins. They are bifunctional organic compounds containing an amino group (–NH₂), a carboxyl group (–COOH), a hydrogen atom, and a variable side chain (R group) attached to the same carbon atom.
📐 General Structure
H₂N – CH(R) – COOH
Where:
–NH₂ = Amino group 🔬
–COOH = Carboxyl group 🧪
R = Variable side chain ✨
Central carbon = α-carbon ⚛️
🔢 Number of Amino Acids in Proteins: 60 – 6000
⚖️ Molecular weight of proteins: 43,000 – 50,000,000 daltons (1 dalton (Da) = 1 amu).
🧩 Total Amino Acids: 20
🌟 Essential Amino Acids: 10
🌱 Non-essential Amino Acids: 10
OR
What are fatty acids? Give their examples and chemical nature.
Answer
🛢️ Definition of Fatty Acids
Fatty acids are building blocks of lipids. Fatty acids are long-chain saturated or unsaturated carboxylic acids that combine with glycerol to form fats and oils (triesters).
🌟 Examples
Palmitic acid: C₁₅H₃₁COOH (Saturated fatty acid)
Stearic acid: C₁₇H₃₅COOH (Saturated fatty acid)
⚗️ Chemical Nature
Lipids are macromolecules composed of fatty acids. They include oils and fats, which are triesters of glycerol and three long-chain fatty acids. Because they contain three fatty acids, they are called triglycerides or triesters.
Triglycerides = Glycerol + 3 fatty acids → triesters (oils/fats). 🧈
1️⃣5️⃣
Briefly describe any three beneficial impacts of pharmaceutical industry on human society.
Answer
💊 Beneficial Impacts of Pharmaceutical Industry
⏳ Increases life expectancy – Medicines and therapies help people live longer and healthier lives.
🌍 Eradicates and controls diseases – Aims to eliminate diseases like smallpox and control epidemics globally.
😌 Reduces pain and suffering – Provides relief from chronic pain, improving quality of life and mental health.
OR
Give general formula for Alkanes, Alkenes and Alkynes. Identify Alkanes, Alkenes, Alkynes, Cycloalkanes and Aromatics in each of the following.
C₆H₆, C₂H₄, C₃H₄, C₃H₈, C₆H₁₂, C₅H₈, C₄H₆, C₆H₅OH
Answer
⚡ General Formulas
🔗 Alkanes: CₙH₂ₙ₊₂
🔗 Alkenes: CₙH₂ₙ
🔗 Alkynes: CₙH₂ₙ₋₂
🧪 Compound Identification
⚡ C₆H₆: Aromatic (Benzene) 🌸
⚡ C₂H₄: Alkene (Ethene) 🌱
⚡ C₃H₄: Alkyne (Propyne) 🔥
⚡ C₃H₈: Alkane (Propane) 💨
⚡ C₆H₁₂: Cycloalkane/Alkene (Cyclohexane / Hexene) 🔄
⚡ C₅H₈: Alkyne/Cycloalkene (Pentyne / Cyclopentyne) 🧬
⚡ C₄H₆: Alkyne/Cycloalkene (Butyne / Cyclopentene) 🧩
⚡ C₆H₅OH: Aromatic alcohol (Phenol) 💧
1️⃣6️⃣
Write down causes of following diseases:
(i) Diarrheal Diseases (ii) Dysentery (iii) Cholera (iv) Cryptosporidium
(v) Fluorosis (vi) Hepatitis (vii) Hookworm (viii) Typhoid
Answer
🌡️ Water-borne Diseases and Causes
💧 Diarrheal Diseases: Caused by viruses, bacteria, and parasites.
🦠 Dysentery: Caused by bacteria (Shigella, Salmonella, E. coli) or parasites (Entamoeba histolytica, Balantidium coli).
💧 Cholera: Caused by bacteria Vibrio cholerae.
🧫 Cryptosporidium: Caused by waterborne protozoan microbes.
⚠️ Fluorosis: Caused by accumulation of excess fluoride in the body.
🩺 Hepatitis: Caused by viruses (Hepatitis A, B, C, D, E).
🪱 Hookworm: Caused by parasitic hookworms.
🍽️ Typhoid: Caused by bacteria Salmonella typhi.
🟡 Jaundice: Caused by Hepatitis viruses A, B, C, D, E.
OR
Define atmosphere. Discuss its composition. Write down the names of different atmospheric layers with their altitude and temperatures.
Answer
🌍 Definition of Atmosphere
The atmosphere is a layer of gases that surrounds the Earth, held in place by gravity. It is essential for sustaining life as it provides oxygen for respiration, protects from harmful solar radiation, and regulates the climate.
🌬️ Composition of Atmosphere
Nitrogen (N₂) – 78.09%
Oxygen (O₂) – 20.95%
Argon (Ar) – 0.93%
Carbon Dioxide (CO₂) – 0.04% (variable)
Neon (Ne) – 0.0018%
Helium (He) – 0.0005%
Methane (CH₄) – Trace
Water Vapor (H₂O) – 0–4% (varies)
Other gases – Includes ozone (O₃), hydrogen (H₂), and xenon (Xe)
🌤️ Atmospheric Layers
🌦️ Troposphere: Altitude 0–8/15 km, Temperature decreases with altitude (up to –60°C).
🌈 Stratosphere: Altitude 8–15 km to ~50 km, Temperature increases with altitude (up to 0°C) due to ozone absorption of UV radiation.
🌙 Mesosphere: Altitude 50–85 km, Temperature decreases with altitude (as low as –90°C).
🔥 Thermosphere: Altitude 85–600 km, Temperature increases with altitude (up to 2,500°C or more).
🌌 Exosphere: Altitude 600–10,000 km, Temperature very high, can reach up to 2,500°C.
1️⃣7️⃣
What is the cause of acid rain? Explain. Write down the effects of acid rain and global warming.
Answer
🌧️⚠️ Definition
Acid rain occurs when pollutants like SO₂ and NO₂ react with rainwater to form sulfuric and nitric acids, lowering pH below 5.5. It is a harmful effect of air pollution 🌍💨.
🌧️ Cause of Acid Rain
Acid rain is formed when sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) from burning fossil fuels mix with rainwater, creating sulfuric acid (H₂SO₄) and nitric acid (HNO₃), lowering the pH of rain below 5.5.
🌍 Effects of Acid Rain
🏛️ Buildings & Monuments: Erodes marble and limestone, causing deterioration.
🐟 Aquatic Life: Pollutes water with heavy metals, suffocating fish.
🌱 Plants: Damages leaves, reduces growth, and weakens resistance to cold and disease.
🌾 Soil: Increases soil acidity, affecting crop growth and leaching toxic metals.
🌎 Global Warming
Increased CO₂ leads to higher temperatures, melting ice, and extreme weather, compounding acid rain's damage to the environment.
OR
Give difference between primary and secondary air pollutants. Identify as primary or secondary air pollutant SO₂, CH₄, HNO₃, NH₃, H₂SO₄ and O₃.
Answer
🌬️ Primary vs. Secondary Air Pollutants
🟢 Primary Pollutants
👉 Directly emitted into the atmosphere.
Examples: CO₂, SO₂, NOx, CH₄, NH₃.
🔵 Secondary Pollutants
👉 Formed by chemical reactions of primary pollutants in the atmosphere.
Examples: H₂SO₄, O₃, HNO₃, PAN.
🔍 Identification
🟢 SO₂ – Primary pollutant
🟢 CH₄ – Primary pollutant
🔵 HNO₃ – Secondary pollutant
🟢 NH₃ – Primary pollutant
🔵 H₂SO₄ – Secondary pollutant
🔵 O₃ – Secondary pollutant
1️⃣8️⃣
Describe the composition of water. Write degree of Hardness of water on the basis of Dissolved Ca Ions (mg/L).
Answer
🌊 Water is a polar covalent molecule (H₂O) where the oxygen attracts electrons more than hydrogen, giving δ− on O and δ+ on H, making the molecule polar.
💧 Degree of Hardness of Water on the Basis of Dissolved Ca Ions (mg/L)
💦 Soft water → 0 – 16.1 mg/L
🙂 Slightly hard water → 16.1 – 60 mg/L
😐 Moderately hard water → 61 – 120 mg/L
🪨 Hard water → 121 – 180 mg/L
🔴 Very hard water → > 180 mg/L
1️⃣9️⃣
List down the applications of conductometry?
Answer
⚡ Applications of Conductometry
1️⃣ Degree of Dissociation 🧪 – Determine dissociation constant.
2️⃣ Solubility 🌡️ – Measure solubility of sparingly soluble substances.
3️⃣ Reaction Rate ⏱️ – Study rate constant of a reaction.
4️⃣ Titration Endpoint 🎯 – Detect end point of titrations.
OR
Define qualitative analysis. What are organic and inorganic qualitative analyses. Give their examples.
Answer
📝 Qualitative Analysis
✨ Definition: Identification of elements, ions, or compounds present in a sample — focusing on their presence (quality), not quantity. 🔍⚗️
Qualitative analysis is further divided into following types based on chemical tests:
🧪 Types
🔎 Inorganic Qualitative Analysis
🔬 Deals with ions (elements) and inorganic compounds using chemical tests ⚡🧂. Often involves precipitation, flame tests, or chemical reactions.
➡️ Example: Flame test of copper halides shows bluish green colour due to copper presence; Detection of Na⁺, K⁺, Cl⁻, SO₄²⁻.
🔎 Organic Qualitative Analysis
🧪 Identifies classes of organic compounds or functional groups through characteristic colour changes. 🌿🧬
➡️ Example: A white precipitate forms when silver nitrate (AgNO₃) in dilute nitric acid (HNO₃) is added, indicating halide ions (F, Cl, Br, I); Identification of carbohydrates, proteins, fats.
2️⃣ Inorganic Qualitative Analysis
Deals with identifying elements, ions, or simple inorganic compounds.
Examples:
⚡ Identification of cations like Na⁺, Ca²⁺, Fe³⁺.
⚡ Identification of anions like Cl⁻, SO₄²⁻, NO₃⁻.
2️⃣0️⃣
What is error? Write down causes of errors with their %. Write down brief note systematic and random errors with two examples each.
✅ Answer
❌ Error: The numerical difference between observed value and true value.
⚡ Causes of Errors
➡️ 13% Equipment failure ⚙️
➡️ 13% Human error 👩🔬
➡️ 16% Sample preparation 🧪
➡️ 10% Wrong calibration 📏
📊 Types of Errors
(i) Systematic error 🔧
(ii) Random error 🎲
🔧 Systematic Errors / Determinate Errors
➡️ Caused by defects in analytical method or improper functioning of instruments.
➡️ Types: instrumental, observational, environmental, theoretical.
📌 Examples:
1️⃣ Thermometer, pipette, burette, analytical balance showing consistent measurement error. 🌡️
2️⃣ Acid base titration with improperly prepared pH indicator or unclean burette causing early colour change. ⚗️
🎲 Random Errors / Indeterminate Errors
➡️ Caused by variations in procedure, environment, or instrument limitations.
➡️ Unavoidable, may be positive or negative.
📌 Examples:
1️⃣ Measuring mass on analytical balance gives varying readings due to air or moisture effects. ⚖️
2️⃣ Reading burette volume only to nearest 0.1 cm³ introduces unavoidable variation. 📏
🔎 Random errors are reduced by taking multiple readings and averaging results.
OR
Define quantitative analysis. What are the physical and chemical methods of quantitative analysis?
Answer
📝 Quantitative Analysis
✨ Determines the exact amount or concentration of one or more substances in a sample.
🌈 Physical Methods
📊 Measure physical properties such as density, temperature, light absorption, magnetic influences, colour, and texture.
➡️ Techniques: FTIR, AES, trace element analysis, EDS.
🌈 Chemical Methods
⚗️ Use chemical reactions (precipitation, oxidation, neutralization) to determine amounts.
➡️ Techniques: Volumetric analysis, Gravimetric analysis, Combustion analysis.
OR
What is vitamin D? Give its sources and importance.
Answer
☀️ Vitamin D
Definition: A fat-soluble vitamin essential for healthy bones and immunity 🦴🛡️.
🌱🐟🥛 Sources:
☀️ Sunlight
🐟 Fish
🥛 Milk & dairy
💡 Importance:
🦴 Strengthens bones & teeth
🛡️ Supports immune system
🥛 Helps in calcium absorption
✏️ Smart Answers of Section-C (Long-Answer Questions) ✏️
2️⃣1️⃣
State law of mass action and define Kc. Derive an expression for equilibrium constant for a general reaction. Predict, which system at equilibrium, will contain maximum amount of reactant or maximum amount of product:
(i) 2CO₂ ⇌ 2CO + O₂ Kc = 3.1 ×10⁻¹⁸ mol.dm⁻³
(ii) 2O₃ ⇌ 3O₂ Kc = 5.9 ×10⁵⁵ mol.dm⁻³
Answer
📘 Statement of Law of Mass Action (LMA)
At constant temperature, the rate of a chemical reaction is directly proportional to the product of the active masses (molar concentrations) of the reactants, each raised to the power of their stoichiometric coefficients.
➡️ Rate ∝ Active mass of reactants
➡️ Active mass = molar concentration (mol dm⁻³)
👉 Definition of Kc
Kc is the ratio of the product of molar concentrations of products to that of reactants, each raised to the power of their stoichiometric coefficients, at equilibrium and constant temperature.
📗 Derivation of Equilibrium Constant (Kc)
Consider a general reversible reaction:
aA + bB ⇌ cC + dD
➡️ Rate of forward reaction ∝ [A]ᵃ [B]ᵇ OR Rᵳ = Kᵳ [A]ᵃ [B]ᵇ (Kᵳ = specific rate constant for forward reaction)
➡️ Rate of reverse reaction ∝ [C]ᶜ [D]ᵈ OR Rᵣ = Kᵣ [C]ᶜ [D]ᵈ (Kᵣ = specific rate constant for reverse reaction)
At equilibrium:
Rᵳ = Rᵣ
Kᵳ [A]ᵃ [B]ᵇ = Kᵣ [C]ᶜ [D]ᵈ
Kᵳ/Kᵣ = [C]ᶜ [D]ᵈ / [A]ᵃ [B]ᵇ
✅ Kc = Kᵳ/Kᵣ = [C]ᶜ [D]ᵈ / [A]ᵃ [B]ᵇ
Or simply: Kc = [Products]/[Reactants]
📊 Prediction of Reactant or Product Amount
🔎 Rule:
➡️ If Kc >> 1 → Products are favored ✅
➡️ If Kc << 1 → Reactants are favored ✅
(i) 2CO₂ ⇌ 2CO + O₂
Kc = 3.1 ×10⁻¹⁸ mol.dm⁻³
Since Kc is extremely small (<<1):
👉 Reaction favors reactants
👉 System contains maximum amount of CO₂ 🌫️
(ii) 2O₃ ⇌ 3O₂
Kc = 5.9 ×10⁵⁵ mol.dm⁻³
Since Kc is extremely large (>>1):
👉 Reaction favors products
👉 System contains maximum amount of O₂ 🌬️
2️⃣2️⃣
State and explain Bronsted-Lowry acid-base theory or Lewis concept of acids and bases with examples? Explain with an example that water is a Bronsted-Lowry acid as well as Bronsted-Lowry base. Give limitations of Bronsted-Lowry theory.
Answer
📘 Brønsted–Lowry Acid–Base Theory (1923)
Proposed by Johannes Brønsted and Thomas Lowry.
🔹 Definitions
👉 Acid → A substance (molecule or ion) that donates a proton (H⁺). Acid = Proton donor
👉 Base → A substance (molecule or ion) that accepts a proton (H⁺). Base = Proton acceptor
✅ Example:
HCl + NH₃ → NH₄⁺ + Cl⁻
HCl donates H⁺ → Acid
NH₃ accepts H⁺ → Base
🔁 Conjugate Acid–Base Pair
A conjugate acid–base pair consists of two species that differ by one proton (H⁺).
➡️ When an acid loses H⁺, it forms its conjugate base.
➡️ When a base gains H⁺, it forms its conjugate acid.
✅ Example:
HCl + H₂O ⇌ H₃O⁺ + Cl⁻
HCl → Acid
Cl⁻ → Conjugate base
H₂O → Base
H₃O⁺ → Conjugate acid
💧 Water is Both Bronsted-Lowry Acid and Base (Amphoteric Nature)
Water can act as both Brønsted acid and base depending on the reaction.
1️⃣ Water as a Base:
HCl + H₂O ⇌ H₃O⁺ + Cl⁻
HCl donates H⁺ → Acid
H₂O accepts H⁺ → Base
Forms H₃O⁺ (hydronium ion)
2️⃣ Water as an Acid:
NH₃ + H₂O ⇌ NH₄⁺ + OH⁻
NH₃ accepts H⁺ → Base
H₂O donates H⁺ → Acid
Forms OH⁻ ion
👉 Therefore, water is amphoteric ✅
📗 Lewis Concept of Acids and Bases (1923)
Proposed by G. N. Lewis.
🔹 Definitions
👉 Lewis Acid → Electron pair acceptor
👉 Lewis Base → Electron pair donor
👉 No need for H⁺ in Lewis theory
✅ Example 1:
H⁺ + H₂O → H₃O⁺
H⁺ accepts electron pair → Lewis acid
H₂O donates electron pair → Lewis base
✅ Example 2:
NH₃ + BF₃ → NH₃→BF₃
NH₃ donates lone pair → Lewis base
BF₃ accepts lone pair → Lewis acid
Forms coordinate covalent bond
⚠ Limitations of Brønsted–Lowry Theory
1️⃣ Only explains reactions involving proton (H⁺) transfer.
2️⃣ Cannot explain acid–base reactions without H⁺ (e.g., BF₃ + NH₃).
3️⃣ Does not explain acidic behavior of some non-protonic substances (like AlCl₃, SO₂, SO₃, CO₂). ❌
4️⃣ Does not describe strength based on electron pair acceptance.
5️⃣ Cannot explain basicity of OH⁻ compounds like NaOH, KOH 🧪.
6️⃣ Proton donor & acceptor must co-exist, but many reactions don’t follow this 🌀.
OR
State three different theories about concepts of acids and bases with one example and also indicate one limitation of each concept. Which of the following is/are Arrhenius acids and bases?
(a) Ca(OH)₂ (b) HNO₃ (c) NaOH (d) H₂SO₄ (e) KOH
Answer
📘 Three Theories of Acids and Bases
1️⃣ Arrhenius Theory (1887)
🔹 Definition:
👉 Arrhenius Acid → Produces H⁺ (or H₃O⁺) in aqueous solution.
👉 Arrhenius Base → Produces OH⁻ in aqueous solution.
✅ Example:
HNO₃(aq) → H⁺(aq) + NO₃⁻(aq)
NaOH(aq) → Na⁺(aq) + OH⁻(aq)
⚠ Limitation:
🌊 Only valid in aqueous solutions.
❌ Doesn’t explain ammonia’s basicity & CO₂’s acidity.
🧪 H⁺ ions react with water to form H₃O⁺.
2️⃣ Brønsted–Lowry Theory (1923)
🔹 Definition:
👉 Acid → Proton (H⁺) donor
👉 Base → Proton (H⁺) acceptor
✅ Example:
NH₃ + H₂O ⇌ NH₄⁺ + OH⁻
H₂O donates H⁺ → Acid
NH₃ accepts H⁺ → Base
⚠ Limitation:
Explains only proton-transfer reactions (cannot explain reactions without H⁺ like BF₃ + NH₃).
3️⃣ Lewis Theory (1923)
🔹 Definition:
👉 Lewis Acid → Electron pair acceptor
👉 Lewis Base → Electron pair donor
👉 No need for H⁺ in Lewis theory.
✅ Example:
NH₃ + BF₃ → NH₃→BF₃
NH₃ donates lone pair → Lewis base
BF₃ accepts lone pair → Lewis acid
⚠ Limitation:
Too broad; does not clearly distinguish between acid–base and other chemical reactions.
📝 Which of the Following are Arrhenius Acids and Bases?
✅ Arrhenius Acids (produce H⁺ in water): HNO₃, H₂SO₄
✅ Arrhenius Bases (produce OH⁻ in water): Ca(OH)₂, NaOH, KOH
2️⃣3️⃣
Define functional group. Write different functional groups which contain carbon, hydrogen and oxygen.
Answer
📘 Definition
An atom or group of atoms or multiple bonds whose existence in an organic compound gives distinctive qualities to that compound is called a functional group.
📗 Functional Groups Containing Carbon, Hydrogen and Oxygen
The organic compounds containing carbon, hydrogen and oxygen as functional groups are alcohols, ethers, aldehydes, ketones, carboxylic acids and esters.
| ⚡ Functional Group | 📛 Name of F.G | 📐 General Formula | 📘 Class Formula | 🏷️ Class Name | 🧪 Examples |
| –OH | Hydroxyl | CnH2n+1–OH | R–OH | Alcohol | CH3OH, C2H5OH |
| –CH2–OH | Primary | CnH2n+1–OH | RCH2–OH | Primary Alcohol | CH3OH, C2H5OH |
| >CH–OH | Secondary | CnH2n+1–OH | R2CH–OH | Secondary Alcohol | (CH3)2CHOH |
| >C–OH | Tertiary | CnH2n+1–OH | R3C–OH | Tertiary Alcohol | (CH3)3COH |
| –O– | Ether linkage | CnH2n+1–OR | R–O–Rʹ | Ether | CH3–O–CH3 |
| –CHO | Aldehydic | CnH2n+1–CHO | R–CHO | Aldehydes | H–CHO, CH3–CHO |
| –COR | Keto | CnH2n+1–COR | R–CO–Rʹ | Ketones | CH3–CO–CH3 |
| –COOH | Carboxylic | CnH2n+1–COOH | R–COOH | Carboxylic acid | H–COOH, CH3–COOH |
| –COOR | Ester | CnH2n+1–COOR | Rʹ–COO–R | Ester | CH3–CO–OCH3 |
OR
Define nomenclature and describe IUPAC nomenclature rules for alkynes and alkanes. Write down IUPAC names of following:
Answer
📘 Definition of Nomenclature
Nomenclature is the process of naming chemical compounds using systematic rules so that each compound has a unique and recognizable name.
📗 IUPAC Nomenclature
The International Union of Pure and Applied Chemistry (IUPAC) developed a standardized system (Prefix–Parent–Suffix) to name organic compounds.
🔹 Parts of IUPAC Name
1️⃣ Root/Parent Hydrocarbon → Number of carbons
2️⃣ Suffix → Functional group/family
3️⃣ Prefix → Substituents
📘 Rules for Naming Alkanes
1️⃣ Longest Chain Rule – Select longest continuous chain, add suffix “–ane”.
2️⃣ Lowest Number Rule – Number from end nearest substituent.
3️⃣ Prefix with Position – Write substituent with its carbon number.
4️⃣ One Word Name – Use hyphens (–) and commas (,).
5️⃣ Multiplicity – Use di, tri, tetra for repeated substituents.
6️⃣ Alphabetical Order – Arrange substituents alphabetically.
7️⃣ Larger Radical Preference – Number from end nearer larger substituent.
📘 Rules for Naming Alkynes
1️⃣ Longest Chain Rule – Select chain with triple bond, suffix “–yne”.
2️⃣ Lowest Number Rule – Number from end nearest triple bond.
3️⃣ One Word Name – Mention position of triple bond.
4️⃣ Alkadiyne – Use di, tri, tetra for multiple triple bonds.
5️⃣ Double Bond Preference – Double bond gets priority if at same location.
6️⃣ Lowest Number Rule – If both double & triple bonds present, start from nearest bond.
📝 IUPAC Names of Given Compounds
2️⃣4️⃣
What are the main sources of organic compounds? Mention with special reference of coal, petroleum and natural gas.
Answer
📘 Sources of Organic Compounds
There are two principal natural sources of organic compounds: living organisms and minerals (coal, petroleum, natural gas).
🐄 Animals
Proteins (eggs, meat, fish), fats (milk, butter, cheese), vitamins, hormones, urea, uric acid.
🌱 Plants
Carbohydrates (sugars, starch, cellulose), proteins (pulses, beans), oils (sunflower, olive, soybean), vitamins (fruits), gums, rubbers, dyes, drugs, fibres (cotton), organic acids (citric, oxalic, tartaric).
🪨 1. Coal
Coal = “Black Gold”, a solid fossil fuel mainly carbon with O, H, N, S.
🔹 Formation: From dead plants buried millions of years ago → peat → coal (carbonization under high pressure & temperature).
🔹 Types: Five forms depending on carbon content, volatile matter, moisture.
🔥 2. Natural Gas
Mixture of hydrocarbons (mainly methane ~85%). Origin similar to coal/petroleum.
🔹 Occurrence: Found at Sui (Pakistan).
🔹 Formation: Decay of dead animal matter, usually above petroleum deposits.
🔹 Uses:
1️⃣ Domestic & industrial fuel.
2️⃣ Fertilizer (urea).
3️⃣ Automobile fuel (CNG).
4️⃣ Carbon black production.
⛽ 3. Petroleum
Thick, dark liquid fossil fuel (C₁–C₄₀ hydrocarbons: alkanes, alkenes, cycloalkanes, aromatics + small inorganic compounds).
🔹 Separation: Fractional distillation → separates into fractions by boiling points (gasoline, kerosene, diesel, lubricants, etc.).
OR
What do you mean by diversity and magnitude of organic compounds? Give at least 5 reasons.
Answer
📘 Diversity & Magnitude of Organic Compounds
Over 10 million organic compounds exist — far more than all other elements combined. Carbon’s unique properties explain this vast diversity.
1️⃣ Tetravalency
Carbon bonds with four atoms at once, forming stable structures.
2️⃣ Catenation
Self-linking property → long chains/rings of C–C bonds. Stronger C–C bonds (355 kJ/mol) compared to Si–Si (200 kJ/mol).
3️⃣ Isomerism
Same molecular formula → different structures. Example: C₅H₁₂ (pentane) has 3 isomers.
4️⃣ Multiple Bond Formation
Carbon forms double/triple bonds: C=C, C≡C, C=O, C=S, C≡N. Adds variety of structures.
5️⃣ Strength of Covalent Bonds
Small size → strong covalent bonds with C, H, O, N, halogens → stability and diversity.
OR
Give classification of organic compounds and the important characteristic of organic compounds.
Answer
📘 Classification of Organic Compounds
Organic compounds are broadly divided into:
1️⃣ Open chain (acyclic) compounds
2️⃣ Closed chain (cyclic) compounds
🔹 1. Open Chain or Acyclic Compounds
Carbon atoms linked in open chains (straight or branched). Also called aliphatic compounds.
➡️ Examples: n-pentane, isopentane, n-butane, isobutane.
Types:
(i) Saturated (alkanes, CnH2n+2)
(ii) Unsaturated (alkenes CnH2n, alkynes CnH2n−2)
📊 Difference: Saturated vs Unsaturated Hydrocarbons
✅ Saturated: C–C single bonds, more H per C, less reactive, substitution reactions, stable, burn with blue flame.
✅ Unsaturated: C=C or C≡C bonds, fewer H per C, more reactive, addition reactions, less stable, burn with yellow sooty flame.
🔹 2. Closed Chain or Cyclic Compounds
Carbon atoms form rings.
➡️ Examples: cyclobutane, benzene, phenol.
Types:
(a) Homocyclic (only carbon atoms in ring)
(b) Heterocyclic (rings with O, N, S atoms)
🌀 Homocyclic Compounds
(i) Aromatic (benzene ring, alternating double bonds, e.g. benzene, naphthalene).
(ii) Alicyclic (non-benzenoid rings, e.g. cyclopentane).
🧪 Heterocyclic Compounds
Rings with carbon + other atoms (O, N, S). Example: pyridine, furan.
📗 General Characteristics of Organic Compounds
1️⃣ Presence of carbon + few elements (H, O, N, S, halogens).
2️⃣ Living origin (plants, animals, minerals).
3️⃣ Covalent nature (non-ionic).
4️⃣ Solubility: insoluble in water, soluble in organic solvents.
5️⃣ Non-conductors of electricity.
6️⃣ Low melting/boiling points, volatile.
7️⃣ Less stable than inorganic compounds.
8️⃣ Combustible, burn to form CO₂.
9️⃣ Slow reactivity, often low yield.
2️⃣5️⃣
What are Lipids? Write down the sources and uses of lipids. Write five differences between Fats and Oils.
Answer
📘 Definition
Lipids are naturally occurring heterogeneous organic compounds (C, H, O, sometimes P & N) including fats, oils, waxes. They are insoluble in water but soluble in organic solvents (ether, benzene, chloroform).
🌱 Sources of Lipids
🐟 Animals → Marine animals (salmon, whales), butter, ghee, cheese.
🌻 Plants → Sunflower, coconut, groundnut, corn, cotton seed, olive.
⚡ Uses of Lipids
1️⃣ Transport fatty acids & fat-soluble vitamins (A, D, E, K).
2️⃣ Some lipids reduce cholesterol.
3️⃣ Used in cooking & frying.
4️⃣ Used in detergents, soaps, cosmetics, polishes, paints.
5️⃣ Activate enzymes.
6️⃣ Stored in adipose tissue; milk gives butter & ghee for food & bakery.
📊 Differences between Fats and Oils
✅ Fats:
• Solid at room temperature.
• Usually from animals.
• Saturated compounds.
• High melting points.
• Increase cholesterol.
✅ Oils:
• Liquid at room temperature.
• Usually from plants.
• Unsaturated compounds.
• Low melting points.
• Maintain cholesterol.
OR
What are proteins and peptide bond? How peptide bond is formed in dipeptides and tripeptides? Write down the range of Number of Amino Acids & molecular weights of Proteins. Give importance & sources of proteins.
Answer
📘 Definition of Proteins
Proteins (Greek “Proteios” = first) are macromolecular nitrogenous compounds made of amino acids linked by peptide bonds. They are polymers of amino acids and yield amino acids upon hydrolysis.
📗 Definition of Peptide Bond
A peptide bond is an acid-amide linkage formed between amino acids by elimination of water. Thousands of amino acids linked form proteins.
🧪 Formation
• Two amino acids → dipeptide.
• Three amino acids → tripeptide.
• Many amino acids → polypeptide/protein.
🔢 Range of Amino Acids & Molecular Weights
• Number of amino acids in proteins: 60 – 6000.
• Molecular weight: 43,000 – 50,000,000 daltons (1 Da = 1 amu).
• Total amino acids: 20.
• Essential amino acids: 10.
• Non-essential amino acids: 10.
🌱 Sources & Importance of Proteins
1️⃣ Animal proteins → meat, poultry, fish, eggs (essential for protoplasm).
2️⃣ Enzymes → proteins catalyzing reactions; used in pharmaceuticals.
3️⃣ Hides → proteins used for leather (shoes, jackets, sports goods).
4️⃣ Bones → yield gelatin, used in bakery.
5️⃣ Plant proteins → pulses, beans, legumes, used as food.
2️⃣6️⃣
Describe in detail nucleic acids, RNA and DNA. Give five points to differentiate between DNA and RNA. Write down importance of deoxyribonucleic acid (DNA).
Answer
📘 Definition
Nucleic acids were discovered by Friedrich Miescher in 1869. They are biopolymers (long-chain macromolecules) formed by polymerization of nucleotides. Elements present: C, H, O, N, and P.
📗 DNA (Deoxyribonucleic Acid)
• Double-stranded helix.
• Sugar: deoxyribose.
• Bases: A, G, C, T.
• Found mainly in nucleus (also mitochondria).
📗 RNA (Ribonucleic Acid)
• Single-stranded molecule.
• Sugar: ribose.
• Bases: A, G, C, U.
• Found in nucleolus, cytoplasm, ribosomes.
• Types: mRNA, tRNA, rRNA.
📊 DNA vs RNA Comparison
| Parameter | DNA | RNA |
| Pentose Sugar | Deoxyribose | Ribose |
| Bases | A, G, C, T | A, G, C, U |
| Strands | Double-stranded helix | Single-stranded |
| Size | Large polymers | Smaller, variable |
| Stability | Stable, long-lived | Unstable, short-lived |
| Location | Nucleus (also mitochondria) | Cytoplasm, ribosomes |
| Function | Stores genetic info | Protein synthesis regulation |
| Types | One kind | Three types (mRNA, tRNA, rRNA) |
🌍 Importance of DNA
• Stores genetic information.
• Controls heredity and traits.
• Directs protein synthesis.
• Maintains cellular functions.
• Basis of biotechnology, genetic engineering, forensic science.
OR
What are vitamins. Differentiate its two types with their sources. Name the diseases caused by the deficiency of both types of vitamins.
Answer
📘 Definition
Vitamins are essential nutrients required in small amounts for normal growth and metabolism. Discovered by Hopkins (1912) and named by Funk.
📗 Types of Vitamins
1️⃣ Water-Soluble → B-complex (10 vitamins), Vitamin C.
2️⃣ Fat-Soluble → Vitamins A, D, E, K.
📊 Vitamins Comparison
| Vitamin | Sources | Importance | Deficiency Diseases |
| A | Butter, fish, eggs, milk, cheese, carrots, liver | Eyes (visual pigments), skin | Night blindness, xerophthalmia, dry skin |
| B-complex | Wheat, rice, eggs, milk, meat, liver, nuts, yeast | Nerves, skin | Beri beri, dermatitis, hair loss, tongue/lip inflammation |
| C (Ascorbic acid) | Oranges, lemon, tomatoes, green peppers | Wound healing, prevent bleeding & cold | Scurvy (swollen gums, reopened wounds) |
| D | Fish liver, dairy, mushrooms, sunlight | Bones, teeth (Ca & P metabolism) | Rickets (soft, weak bones in children) |
| E | Plant oils, leafy vegetables | Cell membrane, reproduction | Sterility, haemolysis (fragile RBCs) |
| K | Green vegetables (spinach, cabbage), cereals | Blood clotting factor | Haemorrhage (delayed clotting) |
2️⃣7️⃣
What is saponification? Describe the raw materials used in the preparation of soap. Describe process of Saponification with the help of flow sheet diagram.
Answer
📘 Saponification
The chemical process for the preparation of soap is called saponification. It is the reaction of triglycerides (fats/oils) with sodium hydroxide (NaOH) or potassium hydroxide (KOH) to form glycerol and fatty acid salts (soap).
⚡ Role of Alkali
• NaOH → Produces hard soap.
• KOH → Produces soft soap (more soluble, used in shaving creams & textile industry).
🧪 Raw Materials
1️⃣ Oils & fats (triglycerides).
2️⃣ Alkali (NaOH or KOH).
3️⃣ Water (solvent).
4️⃣ Additives (fragrance, color, antiseptics).
📊 Flow Sheet Diagram (Process)
Oils/Fats ➡️ Alkali (NaOH/KOH) ➡️ Heating ➡️ Saponification Reaction ➡️ Soap + Glycerol ➡️ Cooling & Solidification ➡️ Cutting into bars.
OR
Define Atmosphere. Enlist the layers of atmosphere. Differentiate between troposphere and stratosphere.
Answer
📘 Definition of Atmosphere
The atmosphere is a layer of gases surrounding the Earth, held by gravity. It is essential for life, weather, and climate.
📗 Layers of Atmosphere
1️⃣ Troposphere
2️⃣ Stratosphere
3️⃣ Mesosphere
4️⃣ Thermosphere
5️⃣ Exosphere
📊 Troposphere vs Stratosphere
| Parameter | Troposphere | Stratosphere |
| Altitude | 0 – 12 km | 12 – 50 km |
| Temperature | Decreases with height | Increases with height (due to ozone) |
| Weather | Contains clouds, rain, storms | No weather phenomena |
| Composition | Mainly N₂, O₂, CO₂, water vapor | Contains ozone layer |
| Importance | Supports life & weather | Protects from harmful UV rays |
2️⃣8️⃣
Justify that electrochemical methods depend upon electrochemical cells.
Answer
📘 Electrochemical Methods
Electrochemical methods are analytical techniques that measure potential, charge, or electrical properties of a solution. These methods rely on **electrochemical cells** to provide voltage and current for reactions.
⚡ Electrochemical Cell
• Consists of two half-cells: anode (e.g. Zn) and cathode (e.g. Cu).
• Electrodes are dipped in electrolytic solutions (ZnSO₄ at anode, CuSO₄ at cathode).
• Connected by a salt bridge (NaCl) for ionic connectivity.
• Anode → oxidation (negative electrode).
• Cathode → reduction (positive electrode).
🧪 Working Principle
• Voltage source drives ion movement.
• Chemical reactions at electrodes generate current.
• Current depends on concentration of electroactive species.
• Thus, electrochemical cells are the foundation of electrochemical methods.
OR
What is Titrimetric Analysis? Describe how it is performed with diagram.
Answer
📘 Definition
Titrimetric analysis (volumetric analysis) determines the concentration of a substance by reacting it with a solution of known concentration (titrant).
📗 Key Terms
• 🔹 Titration → Comparison of volumes of known vs unknown solutions.
• 🔹 Titrant → Solution of known concentration (e.g. NaOH, HCl).
• 🔹 Analyte → Substance being analyzed (e.g. NaCl, gold).
• 🔹 Indicator → Shows end point by color change (litmus, phenolphthalein, methyl orange).
🧪 General Reaction
aA + tT → Product
(a = moles of analyte, t = moles of titrant).
📊 Process (Flow Diagram)
1️⃣ Burette → contains titrant (known solution).
2️⃣ Flask → contains analyte (unknown solution).
3️⃣ Add indicator to flask.
4️⃣ Titrant added dropwise until end point (color change).
5️⃣ Volume of titrant used → concentration of analyte calculated.
🔎 Diagram (Text Form)
Burette (titrant) ➡️ Flask (analyte + indicator) ➡️ Dropwise addition ➡️ Neutralization ➡️ End point (color change) ➡️ Calculation of concentration.
2️⃣9️⃣
Explain the process of preparation of sugar from sugarcane.
Answer
📘 Preparation of Sugar from Sugarcane
The process of sugar production from sugarcane involves six main steps:
1️⃣ Extraction of Juice
Sugarcane is crushed in mills to extract juice.
2️⃣ Clarification
Juice is heated and treated with lime to remove impurities and neutralize acids.
3️⃣ Concentration
The clarified juice is evaporated in multiple-effect evaporators to form thick syrup.
4️⃣ Crystallization
Syrup is further boiled in vacuum pans to form sugar crystals.
5️⃣ Separation
Crystals are separated from molasses using centrifuges.
6️⃣ Drying & Packaging
Sugar crystals are dried, graded, and packed for use.
📊 Flow Sheet (Text Form)
Sugarcane → Crushing → Juice Extraction → Clarification → Concentration → Crystallization → Separation → Drying → Packaging.
3️⃣0️⃣
What is Ozone? How does Ozone depletion occur by Chlorofluorocarbons (CFCs) also mention some adverse impact of it?
Answer
📘 Ozone
Ozone (O₃) is a triatomic molecule of oxygen present in the stratosphere. It forms the **ozone layer**, which absorbs harmful ultraviolet (UV) radiation from the sun, protecting life on Earth.
⚡ Ozone Depletion by CFCs
• Chlorofluorocarbons (CFCs) released from refrigerators, air conditioners, and aerosols rise to the stratosphere.
• UV radiation breaks down CFCs, releasing chlorine atoms.
• Chlorine reacts with ozone (O₃), breaking it into oxygen (O₂) and reducing ozone concentration.
• One chlorine atom can destroy thousands of ozone molecules.
🌍 Adverse Impacts of Ozone Depletion
1️⃣ Increased UV radiation reaching Earth.
2️⃣ Skin cancer and eye diseases (cataracts).
3️⃣ Reduced crop yield and damage to plants.
4️⃣ Harmful effects on aquatic life (phytoplankton).
5️⃣ Weakening of immune system in humans.
OR
Describe global warming. Justify that greenhouse effect leads to global warming.
Answer
📘 Definition of Global Warming
Global warming is the gradual rise in Earth’s average surface temperature due to increased greenhouse gases, especially CO₂.
⚡ Reason
Earth’s average temperature (~15°C) is rising due to long-term climate change caused by greenhouse gases trapping heat.
🌍 Greenhouse Effect
• CO₂ and other gases absorb infrared radiation from Earth’s surface.
• Prevents heat escape, keeping Earth warm at night.
• Higher CO₂ → stronger greenhouse effect → global warming.
🔹 Greenhouse Gases
CO₂, CH₄, N₂O, water vapors, ozone.
📊 Effects of Global Warming
1️⃣ Rising atmospheric temperature (~0.05°C annually).
2️⃣ More frequent extreme weather (floods, cyclones).
3️⃣ Melting glaciers → rising sea levels → flooding of low-lying areas.
4️⃣ Acid rain, irregular crop patterns.
5️⃣ Lifestyle changes and ecological imbalance.
✅ Prevention
Reduce greenhouse gas emissions, use renewable energy, improve energy efficiency, adopt sustainable practices in transport & agriculture.
3️⃣1️⃣
Describe Gas Chromatography with diagram also write two uses of gas chromatography.
Answer
📘 Definition
Gas Chromatography (GC) or Gas-Liquid Chromatography is a technique used for separation, identification, and quantification of volatile organic compounds. It works on the principle of **partition chromatography** between a mobile phase (gas) and a stationary phase (liquid/solid inside a column).
⚡ Purpose
• Separation of compounds with high volatility.
• Suitable for low molecular weight and thermally stable compounds.
🔹 Phases
• Mobile Phase → Inert carrier gas (e.g. helium, nitrogen).
• Stationary Phase → Viscous liquid coated on solid support (e.g. silica) packed in a long capillary column.
🧪 Principle
• Sample injected → carried by mobile phase gas → passes through stationary phase column.
• Components separate based on affinity to stationary vs mobile phase.
• Detector records retention time → chromatogram produced.
📊 Diagram (Text Form)
Sample Injector ➡️ Carrier Gas ➡️ Column (stationary phase) ➡️ Detector ➡️ Chromatogram (graph of peaks).
🌍 Uses of Gas Chromatography
1️⃣ Separation of volatile mixtures (e.g. hydrocarbons in petroleum).
2️⃣ Qualitative & quantitative analysis of food, drugs, pollutants.
✅ Advantages
• Fast analysis.
• High sensitivity.
• Good separation efficiency.
• Requires small sample.
OR
Describe HPLC in detail.
Answer
📘 Definition
HPLC (High Performance Liquid Chromatography) is a technique for rapid separation of compounds using high-pressure pumps to pass liquid mobile phase through a column packed with absorbent material.
⚡ Instrument Components
• Reservoir (mobile phase).
• Pump (ensures high pressure flow).
• Injector (introduces sample).
• Column (stationary phase for separation).
• Detector (records elution).
• Computer (data acquisition).
🧪 Working
• Sample injected → mobile phase pumped through column → components separated based on affinity.
• Detector senses elution → chromatogram produced.
🌍 Applications
• Drug discovery & pharmaceutical analysis.
• Clinical & cosmetic analysis.
• Environmental chemistry (pollutants).
• Biochemical genetics.
OR
What is spectroscopy? How is it used in the chemical analysis of a substance? Also discuss its types.
Answer
📘 Definition
Spectroscopy is the study of the interaction of light (electromagnetic radiation) with matter as a function of wavelength or frequency. It is widely used in chemistry for identification of substances through their **emission or absorption spectra**.
⚡ Usage in Chemical Analysis
• Determines concentration of atomic, molecular, or ionic species.
• Instruments: spectrometer, spectrophotometer, spectrograph.
• Provides both qualitative (identity) and quantitative (amount) information.
📗 Types of Spectroscopy
🔹 1. Ultraviolet & Visible Spectroscopy (Electronic Spectroscopy)
• Measures absorption of UV/visible light by compounds.
• Principle: interaction of UV light with electrons → absorption spectrum.
• Wavelength range: 192 – 900 nm.
🔹 2. Infrared Spectroscopy (Vibrational Spectroscopy)
• Introduced in 1950, cost-effective and non-hazardous.
• Identifies functional groups in organic molecules, food, polymers, industrial products.
• Wavelength range: 2.5 – 15 μm (wave number 4000 – 625 cm⁻¹).
• Principle: IR radiation absorbed → molecular vibrations; transmitted energy recorded.
✅ Conclusion
Spectroscopy is a powerful analytical tool that helps in **identifying, quantifying, and characterizing** chemical substances by studying how they interact with light.
3️⃣2️⃣
Differentiate between Soft Water and Hard Water and describe different methods of removing temporary and permanent hardness. Write down 5 disadvantages of hard water.
Answer
📘 Soft Water• Contains very small amounts of Ca²⁺ and Mg²⁺ salts.
• Produces lather easily with soap, no curdy precipitate.
📘 Hard Water
• Contains larger amounts of Ca²⁺ and Mg²⁺ salts (bicarbonates, chlorides, sulphates).
• Does not produce lather with soap, forms curdy precipitate.
📊 Soft Water vs Hard Water
| Property | Soft Water | Hard Water |
| Ca²⁺ & Mg²⁺ salts | Small quantity | Large quantity |
| Soap action | Forms lather easily | Forms curdy precipitate |
| Cleaning | Effective | Ineffective |
⚡ Methods of Removing Hardness
🔹 1. Temporary Hardness by Boiling
Ca(HCO3)2(aq) → CaCO3(s) ↓ + H2O + CO2
Mg(HCO3)2(aq) → MgCO3(s) ↓ + H2O + CO2
🔹 2. Temporary Hardness by Clark’s Method (Lime Process)
Ca(HCO3)2(aq) + Ca(OH)2(aq) → 2CaCO3(s) ↓ + 2H2O(l)
Mg(HCO3)2(aq) + Ca(OH)2(aq) → CaCO3(s) ↓ + MgCO3(s) ↓ + 2H2O(l)
🔹 3. Permanent Hardness by Washing Soda
CaSO4(aq) + Na2CO3(aq) → CaCO3(s) ↓ + Na2SO4(aq)
MgCl2(aq) + Na2CO3(aq) → MgCO3(s) ↓ + 2NaCl(aq)
MgSO4(aq) + Na2CO3(aq) → MgCO3(s) ↓ + Na2SO4(aq)
🌍 Disadvantages of Hard Water
1️⃣ Hampers washing → consumes more soap, no lather.
2️⃣ Leaves stains on clothes, tiles, utensils.
3️⃣ Causes dry, rough hair and possible hair loss.
4️⃣ Leads to dry, itchy skin (eczema-like symptoms).
5️⃣ Corrodes and clogs pipes due to scale deposits.
3️⃣3️⃣
Definition of Water Pollution. Write down its Causes and Effects on Life.
Answer
📘 Definition
Water pollution is the contamination of lakes, rivers, oceans, and groundwater with harmful substances, making water unfit for drinking and unsafe for living organisms.
⚡ Causes
• Dumping of untreated industrial and domestic waste.
• High solubility of water dissolves many pollutants easily.
🌍 Effects on Life
1️⃣ Causes diseases like cholera, typhoid, diarrhea.
2️⃣ Harmful to animals and birds.
3️⃣ Promotes algal bloom → reduces oxygen → harms aquatic life.
4️⃣ Degrades beauty of lakes and rivers.
5️⃣ Unfit for washing and cleaning.
OR
Define pollutant. Enlist the names of seven types of pollutants. What are primary and secondary air pollutants? Give the sources, environmental and health risks of the following: COₓ, SOₓ, NOₓ, lead, ozone.
Answer
📘 Definition of Pollutant
A pollutant is any substance (solid, liquid, or gas) that contaminates the environment (air, water, soil) and makes it toxic or harmful to life.
📗 Seven Types of Pollutants
1️⃣ Carbon oxides (CO, CO₂)
2️⃣ Sulphur oxides (SO₂, SO₃)
3️⃣ Nitrogen oxides (NO, NO₂)
4️⃣ Ozone (O₃)
5️⃣ Particulate matter (dust, smoke)
6️⃣ Heavy metals (lead, mercury)
7️⃣ Hydrocarbons (volatile organic compounds)
⚡ Primary vs Secondary Air Pollutants
• Primary → Directly emitted into atmosphere (CO, SO₂, NO, Pb).
• Secondary → Formed by chemical reactions of primary pollutants (ozone, smog, acid rain).
📊 Major Pollutants: Sources, Environmental & Health Risks
🔹 Carbon monoxide (CO)
• Source: Incomplete combustion of fuels.
• Environmental Risk: Contributes to smog.
• Health Risk: Chest discomfort, visual problems, reduced physical/mental ability.
🔹 Nitrogen oxides (NOₓ)
• Source: Vehicle exhausts, power plants.
• Environmental Risk: Promote pollution, damage plants.
• Health Risk: Respiratory irritation, inflammation.
🔹 Sulphur dioxide (SO₂)
• Source: Burning coal, oil, industrial emissions.
• Environmental Risk: Causes acid rain, damages flora & monuments.
• Health Risk: Breathing problems, harmful for asthma patients.
🔹 Ozone (O₃)
• Source: Secondary pollutant formed by NOₓ + VOCs under sunlight.
• Environmental Risk: Damages plants, reduces crop yield.
• Health Risk: Lung impairment, breathing irritation.
🔹 Particulate Matter (PM)
• Source: Dust, smoke, industrial emissions.
• Environmental Risk: Creates haze, acid rain, harms vegetation.
• Health Risk: Asthma, irregular heartbeat, respiratory discomfort.
🔹 Lead (Pb)
• Source: Industrial waste, old paints, batteries.
• Environmental Risk: Biodiversity loss, neurological issues in animals.
• Health Risk: Learning problems in children, cardiovascular issues in adults.
💥 جونؔ ایلیا 🎯 💥
💔 صرف زندہ رہے ہم تو مر جائیں گے
🌌 سب بچھڑ جائیں گے سب بکھر جائیں گے
🌅 صبح ہوتے ہی سب کام پر جائیں گے
⚡ کیا ستم ہے کہ ہم لوگ مر جائیں گے
🕊️ بے خبر آئے ہیں بے خبر جائیں گے
🔥 جونؔ ایلیا ۔ غزل 🔥
🕊️ ہر طرف ہو رہی ہے یہی گفتگو، تم کہاں جاؤ گے ہم کہاں جائیں گے
⏳ وقت کی اس مسافت میں بے آرزو، تم کہاں جاؤ گے ہم کہاں جائیں گے
🌌 ہیں یہ سرگوشیاں دربدر کوبکو، تم کہاں جاؤ گے ہم کہاں جائیں گے
💔 تھا سراب اپنا سرمایۂِ جستجو، تم کہاں جاؤ گے ہم کہاں جائیں گے
🌙 بس گزرنے کو ہے موسمِ ہائے و ہُو، تم کہاں جاؤ گے ہم کہاں جائیں گے
🌹 گُل زمیں سے ابلنے کو ہے اب لہو، تم کہاں جاؤ گے ہم کہاں جائیں گے؟
🍷 آخرِ شب ہے خالی ہیں جام و سُبو، تم کہاں جاؤ گے ہم کہاں جائیں گے؟
🔥 بس گزرنے کو ہے موسمِ ہاؤ و ہُو، تم کہاں جاؤ گے ہم کہاں جائیں گے؟
💥 غزل ۔۔۔۔ جونؔ ایلیا 💥
💭 جانے کیسے لوگ وہ ہوں گے جو اس کو بھاتے ہوں گے
🔥 میرے بجھنے کا نظارہ کرنے آ جاتے ہوں گے
💔 آنے والوں سے کیا مطلب آتے ہیں آتے ہوں گے
🌌 یوں ہی میرے بال ہیں بکھرے اور بکھر جاتے ہوں گے
💔 وہ جو سمٹتے ہوں گے ان میں وہ تو مر جاتے ہوں گے
🌙 یعنی میرے بعد بھی یعنی سانس لیے جاتے ہوں گے
💥 غزل ۔۔۔۔ جونؔ ایلیا 💥
💭 ہر لمحہ جی رہے ہیں مگر خیریت سے ہیں
🌌 دشتِ گماں کے خاک بسر خیریت سے ہیں
🕊️ اللہ اور تمام بشر خیریت سے ہیں
💧 مژگانِ خشک و دامنِ تر خیریت سے ہیں
🌟 یعنی تمام اہلِ نظر خیریت سے ہیں
🔥 سودائیانِ حال کے سر خیریت سے ہیں
💭 شکوے کی بات ہے، وہ اگر خیریت سے ہیں
🏚️ خاک اڑ رہی ہے اور کھنڈر خیریت سے ہیں
✨ جونؔ! ایک معجزہ ہے اگر خیریت سے ہیں
📜 اور اپنے صاحبانِ ہنر خیریت سے ہیں
⚔️ برگستوان و تیغ و تبر خیریت سے ہیں
🚪 بس در ہے اور بندئہ در خیریت سے ہیں
📖 ورنہ تمام جوشؔ و جگرؔ خیریت سے ہیں
🌙 باقی جو ہیں وہ شام و سحر خیریت سے ہیں
💥 غزل ۔۔۔۔ جونؔ ایلیا 💥
☀️ دھوپ آنگن میں پھیل جاتی ہے
🌆 شہر کوچوں میں خاک اڑاتی ہے
🕰️ میز پر گرد جمتی جاتی ہے
🌙 اب کسے رات بھر جگاتی ہے
💔 بے دلی بھی تو لب ہلاتی ہے
🌸 زندگی خواب کیوں دکھاتی ہے
💭 خواہشِ غیر کیوں ستاتی ہے
😮 ہمنشیں! سانس پھول جاتی ہے
👀 غور کرنے پہ یاد آتی ہے
💔 روز ایک چیز ٹوٹ جاتی ہے
💥 غزل ۔۔۔۔ جونؔ ایلیا 💥
💭 یہ دل کے خواب کی صورت نہ رائیگاں جائے
🌌 یہ شہر شہر کی محنت نہ رائیگاں جائے
💡 یہ خود سے اپنی رفاقت نہ رائیگاں جائے
🌙 کہیں یہ حسنِ طبیعت نہ رائیگاں جائے
💔 ہمارا عہدِ محبت نہ رائیگاں جائے
✨ یہ اجتماع یہ صحبت نہ رائیگاں جائے
🌟 رہے خیال یہ مہلت نہ رائیگاں جائے
🔥 تیرے جنون کی حالت نہ رائیگاں جائے
💥 غزل ۔۔۔۔ جونؔ ایلیا 💥
💭 شوق اس کا کمال ہے، تاحال
😔 جی ہمارا نڈھال ہے، تاحال
⚡ شوقِ بحث و جدال ہے، تاحال
❓ ہر جواب اک سوال ہے، تاحال
💔 دل میں زخمِ کمال ہے، تاحال
🌟 ذہن میں اک مثال ہے، تاحال
🌿 ہوسِ اندمال ہے، تاحال
🌸 آپ اپنی مثال ہے، تاحال
💔 بے امیدِ وصال ہے، تاحال
🌙 وہ جو تھا اک ملال ہے، تاحال
🎨 رنگ بے خدوخال ہے، تاحال
🦌 تو غزل کا غزال ہے، تاحال
💭 تجھ کو پانا محال ہے، تاحال
😔 پر وہی میرا حال ہے، تاحال
💥 غزل ۔۔۔۔ جونؔ ایلیا 💥
🌙 ہم ہیں حیران اپنی حیرت کے
💔 تم نہیں تھے مری طبیعت کے
🌟 کیا عجب عیش تھے شکایت کے
🎁 یہ عطیے ہیں دل کی عادت کے
⚖️ ہم ہی مفتی ہیں اہلسنت کے
🛠️ نہیں خوگر کسی مشقت کے
🌙 ہیں یہ لمحے تمام ہجرت کے
📖 ہیں عجب معجزے حکایت کے
💥 غزل ۔۔۔۔ جونؔ ایلیا 💥
💔 خود کو ہلاک کر لیا، خود کو فدا نہیں کیا
😔 تو نے تو ہم سے آج تک کوئی گلہ نہیں کیا
📜 میں نے بھی ایک شخص کا قرض ادا نہیں کیا
🌟 آپ بہت شریف ہیں، آپ نے کیا نہیں کیا
🙏 ہم نے نہیں کیا وہ کام، ہاں باخُدا نہیں کیا
💡 اُس نے تو کارِ جہل بھی بے علما نہیں کیا
💥 غزل ۔۔۔۔ جونؔ ایلیا 💥
🌙 تھا تو اک شہر خاکساروں کا
😔 اب پتہ کیا ہے دل فگاروں کا
🛏️ بسترا اب کہاں ہے یاروں کا
🕊️ کون پُرساں ہے یادگاروں کا
🌌 مجھ سے کیا ذکر رہ گزاروں کا
🌟 عیش مت پوچھ دعویداروں کا
🐎 نہ پیادوں کا نہ سواروں کا
📚 دہر ہے صرف استعاروں کا
🤝 کیا ہوا جانے جانثاروں کا
🌪️ ایک جلسہ تھا شعلہ خواروں کا
💥 حضرتِ جونؔ ایلیا 💥 🎨 خاتم الشعرا و شاعرِ بے مثل و بے بدل 🎨
🌙 اور ہم ہیں کہ نام کر رہے ہیں
✨ ہم جو یہ اہمتمام کررہے ہیں
🔥 آپ تو قتلِ عام کررہے ہیں
💭 ہم تو خود سے کلام کررہے ہیں
🤝 ہر کسی کو سلام کررہے ہیں
💔 اپنا ہونا حرام کررہے ہیں
📢 ہم یہ اعلانِ عام کررہے ہیں
🥂 ناف پیالے کو جام کررہے ہیں
🙏 اور وہ احترام کررہے ہیں
🌌 کوئے دل میں خرام کررہے ہیں
🕊️ بات ہی ہم تمام کررہے ہیں
🥁 بے سبب دھوم دھام کررہے ہیں
🗡️ تیغ کو بے نیام کررہے ہیں
⏳ دم کو بس دوام کررہے ہیں
🏛️ ہم ابد میں قیام کررہے ہیں
💥 حضرتِ جونؔ ایلیا 💥 🎨 خاتم الشعرا و شاعرِ بے مثل و بے بدل 🎨
💔 بچھڑنا ہے تو جھگڑا کیوں کریں ہم
🔥 کوئی ہنگامہ برپا کیوں کریں ہم
❌ پر اب اس باب کو وا کیوں کریں ہم
⚖️ بھلا گھاٹے کا سودا کیوں کریں ہم
🌟 تمہاری ہی تمنّا کیوں کریں ہم
📜 تو ساری عمر ایفا کیوں کریں ہم
🚶 فقط کمروں میں ٹہلا کیوں کریں ہم
💡 وہ سرمایہ اکٹھا کیوں کریں ہم
😔 تو پھر دنیا کی پروا کیوں کریں ہم
👀 بھلا اندھوں سے پردہ کیوں کریں ہم
🤝 سو خود پر بھی بھروسا کیوں کریں ہم
🍽️ تمہیں راتب مہیا کیوں کریں ہم
🌪️ زمیں کا بوجھ ہلکا کیوں کریں ہم
🕊️ یہاں کارِ مسیحا کیوں کریں ہم
💫 اس کا خیال بھی نہیں اپنا خیال بھی نہیں
🌿 پوشش برگ و گل تو کیا جسم پہ چھال بھی نہیں
📖 سود ہے کیا زیاں ہے کیا اس کا سوال بھی نہیں
🎶 صلح و سلام تو کجا بحث و جدال بھی نہیں
🌟 شوق کمال بھی نہیں خوف زوال بھی نہیں
🌌 آج افق کے دوش پر گرد کی شال بھی نہیں
🍃 باد جنوب بھی نہیں باد شمال بھی نہیں
💔 اس کے ورود کا گماں فرض محال بھی نہیں
⏳ کل تو نڈھال بھی تھا میں آج نڈھال بھی نہیں
🌙 صبح فراق بھی نہیں شام وصال بھی نہیں
🌹 اب تو ہمارے ذہن میں کوئی مثال بھی نہیں
🔥 خود کو تباہ کر لیا اور ملال بھی نہیں
💥 جونؔ ایلیا 🎯 💥
❤️ تم سے مل کر بہت خوشی ہو کیا
🕊️ مجھ کو یکسر بھلا چکی ہو کیا
😔 مجھ سے مل کر اداس بھی ہو کیا
🤔 سوچتی ہو تو سوچتی ہو کیا
🌹 اب بھی تم میری زندگی ہو کیا
🕰️ آخری بار مل رہی ہو کیا
☀️ تو بہت تیز روشنی ہو کیا
🚶♀️ تم بہت دور جا چکی ہو کیا
⚡ شمع امید بجھ گئی ہو کیا
💧 بان تم اب بھی بہہ رہی ہو کیا
🌹 کلاسیکی غزل ✨
🌸 تذکرۂ خجستۂ آب و ہوا نہیں کیا
💔 تو نے تو ہم سے آج تک کوئی گلہ نہیں کیا
🙏 میں نے ترے لحاظ میں تیرا کہا نہیں کیا
💭 یعنی تجھے ابھی تلک میں نے رہا نہیں کیا
🤝 میں نے بھی ایک شخص کا قرض ادا نہیں کیا
🌾 ہم نے بھی اب کی فصل میں شور بپا نہیں کیا
🔥 خود کو ہلاک کر لیا، خود کو فدا نہیں کیا
😊 آپ بہت شریف ہیں، آپ نے کیا نہیں کیا
🙌 ہم نے نہیں کیا وہ کام، ہاں باخُدا نہیں کیا
🚫 اُس نے تو کارِ جہل بھی بے علما نہیں کیا
🎭 غزل از جون ایلیا
😢🔥 تجھ کو تڑپانے کی ہیں تیاریاں
🧠🌀 ہیں بھُلانے کی اسے تیاریاں
😭💔 رو رہی ہیں اب مجھے مت ماریاں
👧💫 خوب ہیں یہ لڑکیاں بےچاریاں
🏛️👔 جو بھی نوکر جونؔ ہیں سرکاریاں
🧳🚶 اُن سے ہیں اپنی جُدا دشواریاں
⛓️😔 کب تلک سہتے رہیں غداریاں
🌊💥 ہونے ہی والی ہیں ندیاں جاریاں
😞⚠️ سُن میاں ہوتی ہیں ان کی خواریاں
😢🌧️ غم کی بھی اپنی ہیں کچھ عیاریاں
🌠💫 ہر نفس ہیں کہکشائیں طاریاں
⛓️⚖️ یہ تو زنجیریں ہیں بےحد بھاریاں
🧪😷 ہیں ہماری اور ہی بیماریاں
💡⚡ چل رہی ہیں روشنی کی آریاں
🥬💸 کیوں نہیں یہ بیچتے ترکاریاں
💔😓 اُس کے پہلو میں مری قلقاریاں
🌹🩸 اس نے کی ہیں خون کی گل کاریاں
▶ Watch Video on YouTube
Click the preview below to open in new window
▶ Click image to watch on YouTube
Get the X-Chemistry National Comprehensive Targeted Guess Paper 2026 for Class 10 Chemistry. Designed specially for Karachi Board students, this paper includes important MCQs, short questions, and long questions expected in the final exams 2026. Prepare smartly and score high with updated Karachi Board notes and exam tips!
🧠
Related Posts:
https://learnchemistrybyinamjazbi.blogspot.com/2025/11/karachi-board-x-chemistry-paper-2025.html
1️⃣. For the reaction 2A(g) + B(g) ⇌ 3C(g), the equilibrium constant expression is:
1. Define any three of the following:
equilibrium constant, reaction quotient, extent of a reaction, pH, Indicator, Neutralization, Titration, alicyclic compounds, aromatic compounds, catenation, aldoses, ketoses, saccharides, functional group, Peptide linkage, saponification, lipids, enzymes, isomerism, Bloor’s reagent, fatty acid, ozone hole, organic chemistry, Biochemistry, Environmental chemistry, Analytical Chemistry, Qualitative Analysis, Quantitative Analysis, accuracy, precision, titrant, analyte, Indicator, parameter
2. Write down three differences between any one of the following:
(i) Troposphere and Stratosphere(ii) reversible and irreversible reactions
(iii) saturated and unsaturated hydrocarbons
(iv) Dextrorotary and Levorotatory Sugars
(v) Quantitative analysis and qualitative analysis
(vi) Titrimetric analysis and gravimetric analysis
(vii) Classical and Instrumental Methods
(viii) fat and water-soluble vitamins.
(ix) DNA and RNA
(x) fat and oil
(xi) Aldoses and ketoses
3. Define chemical equilibrium
state. Why chemical equilibrium is dynamic? Explain it with one example.
OR
Describe the characteristics of equilibrium constant. Why equilibrium constant may or may not have unit? Justify with example.
4. Write down Equilibrium Constant Expression (Kc) and unit of Kc for any 3 of the following balanced reversible reactions.
(i) N2(g) + 2O2(g) ⇌ 2NO2(g)
(ii) H2(g) + I2(g) ⇌ 2HI(g)
(iii) CO2(g) + H2(g) ⇌ CO(g) + H2O(g)
(iv) 2SO2(g) + O2(g) ⇌ 2SO3(g)
(v) N2(g) + 3H2(g) ⇌ 2NH3(g)
(vi) CO(g) + 3H2(g) ⇌ CH4(g) + H2O(g)
6. State vital force theory and how was this
theory discarded by Wohler?
Or
Write the names and structural formulae of
six carbons alkanes, alkenes, alkyne, cycloalkane and aromatic hydrocarbons.
OR
Draw the
structures of following compounds:
(i) 2,3-dimethylpentane
(ii) 3-ethyl-1-hexene
(iii) 2-butyne
(iv)
2,4-hexadiene
(v) 3-methyl-1,4-hexadiyne
(vi) 2-hepten-5-yen
(vii) 2-pentyne
(viii) neopentane
(ix) iso-propyl alcohol
(x) Phenol or toluene
(xi) iso-butane
(xii) Cyclohexane
8. Define salt
and its three types with two examples each. Give three uses of salts. Also
write any three methods of
preparation of salts with equation.
OR Write
one use of enzymes yeast, cellulase and amylase.
OR What is homologous series? Name the any two
common homologous series with examples. Write down the general characteristics of homologous series.
OR
What
is alkyl radicals? Give its type formula and general formula. Explain with
structure different radicals of butane.
What is the difference of alkyl radicals obtained from propane?
9. Elaborate
ionization equation of water. Explain in detail that how water ionization is
related with pH of solution?
OR
Define buffers. What is the composition of buffers? Discuss its importance in our daily life.
10. Write any
three significant uses of Carbohydrates and lipids.
OR
What are amino acids and peptide bond? How peptide bond is formed? Also explain dipeptides & tripeptides.
11. Give
reason:
(i) Why Silicon compounds are lesser than that of Carbon compounds?
(ii) Why pure water is considered as weak electrolyte?
(iii) Justify the petroleum is ‘black gold’.
(iv) Alkanes are said to be saturated hydrocarbons.
(v) Justify that water soluble vitamins are not injurious to health.
(vi) Justify that greenhouse effect leads to global warming
(vii) Justify that “water is solvent”.
(viii) How is vegetable oil is converted into saturated fat (ghee)?
(ix) Why chemical equilibrium is considered dynamic not static?
(x) Why the temperature on top of a mountain is colder than at sea level?
13. What
are Oligosaccharides, Disaccharides and polysaccharides. Give their examples
and sources.
OR
What are the carbohydrates? Explain sources and types of carbohydrates.
14. What are
amino acids and give their general structure? How many Essential and
Non-essential Amino acids are there? Write down the range of Number
of Amino acids and molecular
weights of Proteins
OR
What are fatty acids? Give their examples and chemical nature.
15. Briefly describe any three beneficial impacts of pharmaceutical industry on human society.
16. Write down causes of following
diseases:
(i) Diarrheal Diseases
(ii) Dysentery
(iii) Cholera
(iv) Crytosporidium
(v) Fluorosis
(vi) Hepatitis
(vii) Hookworm
(viii) Typhoid
17. What is
the cause of acid rain? Explain. Write down the effects of acid rain and global
warming.
OR
What are primary and secondary air pollutants? Or Give difference between primary and secondary air pollutants. Identify as primary or secondary air pollutant SO2, CH4, HNO3, NH3, H2SO4 and O3
18. Describe the composition of water. Write degree of Hardness of water on the basis of Dissolved Ca Ions (mg/L)
19. List down
the applications of conductometry?
OR
Describe the composition of water. Write down degree of Hardness of water on the basis of Dissolved Ca Ions.
20. What is error? Write down causes of errors with their %. Write down brief note systematic and random errors with two examples each.
OR
Describe fractional distillation of petroleum with its 5 fractions.
21. A solution of HCl has pH of 2.3.
Calculate its pOH and [H+]?
OR
Find pH, pOH, [OH−] and [H+] of 2.46 × 10−9 M KOH solution.
22. State law of mass action and define Kc. Derive an expression for equilibrium constant for a general reaction.
23. State and explain
Bronsted-Lowry acid-base theory or Lewis concept of acids and bases with
examples? explain with an example that water is a Bronsted-Lowry
acid as well as Bronsted-Lowry base. OR
State three different theories about concepts of acids and
bases with one example and also indicate one limitation
of each concept. Which of the following is/are Arrhenius acids and bases?
(a) Ca(OH)2 (b) HNO3 (c) NaOH (d) H2SO4 (e) KOH
24. Define
functional group. Write different functional groups which contain carbon,
hydrogen and oxygen.
OR
Define nomenclature and describe IUPAC nomenclature rules for alkynes and alkanes. Write down IUPAC names of following:
25. What are the
main sources of organic compounds? Mention with special reference of coal,
petroleum and natural gas.
OR
What do you mean by diversity and magnitude of organic compounds? Give at least 5 reasons.
26. What are Lipids?
Write down the sources and
uses of lipids. Write five
differences between Fats and Oils.
OR
What are proteins and peptide bond? How peptide bond is formed in dipeptides and tripeptides ? Write down the range of Number of Amino acids and molecular weights of Proteins. Give importance and sources of proteins.
27. Describe in detail nucleic acids, RNA and DNA. Write down importance of deoxyribonucleic acid (DNA).
28. Describe process of Saponification with the help of
flow sheet diagram.
OR
Describe fractions of petroleum in detail.
29. Justify that electrochemical methods depend upon electrochemical
cells.
OR What is Titrimetric Analysis? Describe how it is performed with diagram.
30. Explain the process of preparation sugar from sugar cane. OR Describe process of Saponification with the help of flow sheet diagram.
31. What is Ozone? How does Ozone depletion occur by
Chlorofluorocarbons (CFCs) also mention some adverse impact of it?
OR Describe global warming. Justify that greenhouse effect leads to global warming.
32. Describe Gas Chromatography with diagram also write two uses of gas chromatography.
33. What are Soft Water and Hard Water and describe different methods of removing temporary and permanent hardness. Write down 5 disadvantages of hard water.
34. Definition Water Pollution. Write down its Causes and Effects on Life
35. For
the reaction, H2(g) + I2(g)
⇌ 2HI(g) (Kc = 57.0); the
concentrations of H2(g), I2(g) and HI(g) at
time t are:
[H2]t = 0.10 mol dm−3,
[I2]t = 0.20 mol dm−3,
[HI]t = 0.40 mol dm−3
Predict in which direction reaction will move
to achieve equilibrium.
(Answer; Qc (8.0) is less than Kc (57.0), reaction will move in the forward direction)
OR
Equilibrium
occurs when nitrogen monoxide gas reacts with oxygen gas to form nitrogen
dioxide gas
2NO(g) + O2(g) ⇌ 2NO2(g)
At equilibrium at 230oC, the concentrations are
measured to be
[NO] = 0.0542 mol dm−3,
[O2] = 0.127 mol dm−3
and
[NO2] = 15.5 mol dm−3
Calculate the equilibrium constant at this temperature. (Book problem 1; page 8)(Answer; 6.44 x 105 mol-1 dm3)
🧪📚 Answers of Section-B (Short-Answer Questions)
2. Kc has a unit for reactions when the number of moles of reactants and product are not equal,
OR
H₉–. It may exist in 4 isomeric forms.
Answer
Three Uses of Carbohydrates
1. They are main energy providing materials or energy source for the survival of both plants and animals.
2. They sustain plant structure.
3. Carbohydrates, in the form of starch in plants and glucose in mammals, serve as energy storage.
Three Uses of Lipids
1. They act as transporter of fatty acids and fat soluble vitamins (A, D, E and K) in body.
2. They activate the enzymes.
3. Fats and oils are used for cooking and frying of food.
OR
What are amino acids and peptide bond? How peptide bond is formed? Also explain dipeptides & tripeptides.
Answer
Amino acids
Amino acids are building blocks of protein which are bi-functional organic compound containing an acidic carboxyl (–COOH) and a basic amino (–NH₂) groups and a distinct side chain ‘R’ which is different for different amino acids.
Peptide Bond or Linkage
A peptide linkage is an acid-amide bond formed between amino acids by the elimination of water. Due to this linkage protein is formed. When thousands of amino acids polymerize they form protein.
Formation of Peptide Bond
Dipeptides and tripeptides
A protein molecule formed with two amino acids is termed as dipeptide.
A protein molecule formed with three amino acids is termed as tripeptide.
Remaining Solution Coming Soon
Download here