XI-CHEMISTRY Mid-Term Study Paper 2025

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IUPAC Nomenclature of Organic Compounds

 IUPAC Nomenclature of Organic Compounds 

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X-CHEMISTRY Guess Paper 2025

 

Total marks: 60 

 Time: 3 Hours

General Instructions

Section – A; contains 12 MCQs and all of them are to be answered.

Section – B; consists of 12 short-answer questions of which 8 are to be answered (24 marks)

Section – C; consists of 6 Long-answer questions of which 4 are to be answered (24marks)

 

1. For the reaction, 2A_(g)   +  B_(g) ⇌ 3C_(g) the expression for the equilibrium constant is:

(a) [2A][B]/[3C]                      

(b) [A]²[B]/[C]³                             

(c) [3C]/[2A][B]                            

(d) [C]³/[A]²[B]

 

2. Equilibrium constant value “K_c“ is equal to;

(a) Q_c/K_r                                   

(b) K_r /K_f                                         

(c) K_c/Q_c                                          

(d) K_f/K_r 

 

3. NH₃ can be a base according to

(a) Arrhenius theory             

(b) Bronsted-Lowry theory       

(c) Lewis theory                        

(d) both b and c

 

4. Which of the following is a Lewis base?

(a) HNO₃                                   

(b) AlCl₃                                         

(c) HCl                                       

(d) CN⁻

 

5. The general formula of alkynes is

(a) C_nH_2n                                   

(b) C_nH_2n+1                                      

(c) C_nH_2n–2                                      

(d) C_nH_2n+2

 

6. Which of the following is an alcohol?

(a) CH₃CHO                              

(b) CH₃CH₂OCH₃                          

(c) CH₃CH₂OH                                       

(d) HCOOH

 

7. Which one of the following is polysaccharide?

(a) Fructose                              

(b) maltose                                     

(c) starch                                      

(d) None

 

8. cellulose content in Cotton is

(a) 70%                                      

(b) 95%                                           

(c ) 85%                                       

(d) 90%

 

9. Ozone layer is part of

(a) stratosphere                      

(b) mesosphere                             

(c) thermosphere                         

(d) troposphere 

 

10. It used to assess concentration or amount of given atomic, molecular or ionic chemical.

(a) Chromatography             

(b) Spectroscopy                          

(c) Conductometry                       

(d) Potentiometry

 

11. Surfactants reduce the......... of water.

(a) Surface tension                  

(b)  Viscosity                                 

(c) Boiling point                            

(d) Melting point

 

12. The centrifuge machine used for separation of:

(a) Crystal                                 

(b) pH                                               

(c) Mud                                     

(d) Juice

 

13. Insulin which enables our body to use glucose obtained from food or glycogen is basically:

 (a) an enzyme                          

(b) a hormone                               

(c) an starch                            

(d) a mineral

 

14. Vital force theory was introduced by

(a) Robert Boyle                      

(b) J. J. Berzelius                            

(c) Lewis                                      

(d) Wohler 

 

15. Lactose enzymes are used:

(a) in production of bread                                 

(b) to make ice cream sweeter                                  

(c) to make alcohol                                              

(d) to maintain colour

 

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         

(viii) fat and oil

 

3.Define chemical equilibrium state. Why chemical equilibrium is dynamic? Explain it with one examples

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 (K_c) and unit of K_c for any 3 of the following balanced reversible reactions.

(i)     N_2(g) + 2O_2(g) ⇌ 2NO_2(g)                              

(ii) H_2(g) + I_2(g) ⇌ 2HI_(g) 

(iii)  CO_2(g) + H_2(g) ⇌ CO_(g) + H₂O_(g)                    

(iv) 2SO_2(g) + O_2(g) ⇌  2SO_3(g)

(v)  N_2(g)  + 3H_2(g)   ⇌  2NH_3(g)                

(vi) CO_(g)  + 3H_2(g) ⇌  CH_4(g) +  H₂O_(g)

 

5.  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.

 

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. 

 

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, cellulose and amylase.

 

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.  What are amino acids and peptide bond? How peptide bond is formed? Also explain dipeptides & tripeptides.

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 and general formula. Explain with structure different radicals of propane &  butane.

 

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.

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? 

 

20. What is error? Write down causes of errors with their %. Write down brief note systematic and random errors with two examples each. 

22.   State law of mass action and define K_c. 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 examples 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                 

 

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. Define functional group. Write different functional groups which contain carbon, hydrogen and oxygen.

OR

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.

31. What is Ozone? How does Ozone depletion occurs by Chlorofluorocarbons (CFCs) also mention some adverse impact of it?

OR 

Describe global warming. Justify that green house 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, H_2(g) +  I_2(g) ⇌ 2HI_(g) (K_c = 57.0); the concentrations of H_2(g), I_2(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; Q_c (8.0) is less than K_c (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)  + O_2(g) ⇌  2NO_2(g)

At equilibrium at 230^oC, 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)

 

 

 

 

 

IX Chemistry Guess Paper 2025

Total marks: 60

Time: 3 Hours

General Instructions

Section – A; contains 12 MCQs and all of them are to be answered.

Section – B; consists of 12 short-answer questions of which 8 are to be answered (24 marks)

Section – C; consists of 6 Long-answer questions of which 4 are to be answered (24marks)

Q1.   Define any three of the following:

Valency, Electronegativity, electron affinity, Tyndall effect, free radical, molecular ion, mole, molar volume,      empirical and molecular formula, Molarity, concentration, false solution, mass/volume percent, Freezing Point,    absolute zero, allotropy, Dobereiner’s law of Triads, Newland’s law of Octaves, Mendeleev’s Periodic law, Periodicity, periodic trend, modern, periodic law

 

Q2.   Write down three differences between any one of the following:

(i)   Alkali metal and halogens                      

(ii) Ionic, covalent bond and dative bond

(iii) elements, compounds and mixtures   

(iv) Ionic compounds and covalent compounds

(v) Solution, suspension and Colloid          

(vi) metal, metals and metalloids

(vii) Atom and molecule and ion                 

(viii) Molecule and molecular ion and free radical

 

Q3.   What is meant by atomic number and mass number. Define and give uses of isotopes. Discuss the isotopes of Hydrogen or carbon or uranium. Mention the number of electrons, protons and neutrons in following atoms: 

OR

Differentiate between EF and MF. Describe relationship between empirical and molecular formula? Find out      molecular formula of a compound if its empirical formula is CH₂O and molecular mass 60 amu. Complete the    following chart:

Q4.   Identify group and period in the periodic table of the following elements

(i) ₃Li or ₈O or ₁₅P 

(ii) ₉F or ₁₁Na and ₁₇Cl   

(iii) ₁₂Mg or ₁₃ Al or ₁₄Si

OR

An element has 7 (or 1 or 2 or 8) electrons in its M-shell. Answer the following questions:

(i)    Determine its atomic number and give its Electronic configuration.

(ii)   Identify the group, period and block of given element.

(iii) Write down three characteristics of the belonging group. Also Write down the name and symbol of radioactive element of this group.

Q5.   Compare of reactivity of Alkali and Alkaline Earth Metals

OR 

Write down one contribution of any 10 scientists in the field of chemistry. OR write down three significant reasons to study chemistry. 

OR 

Explain the importance of glues and epoxy resins in our society.

        

Q6.   Write chemical formulae of any three of the following compounds:

Sand (SiO₂), Limestone (CaCO₃) ,Sodium nitrate (NaNO₃), table salt (NaCl), sal ammoniac (NH₄Cl), Caustic soda (NaOH), caustic potash (KOH), washing soda (Na₂CO₃.10H₂O), baking soda (NaHCO₃), soda ash (Na₂CO₃), Epsom            salt (MgSO₄.7H₂O),gypsum (CaSO₄.2H₂O), oleum (H₂S₂O₇), marsh gas (CH₄), blue vitriol (CuSO₄.5H₂O), sugar (C₁₂H₂₂O₁₁), ethyl alcohol, Acetylene, Ethylene,.

OR

What is coordinate covalent bond? Explain with two examples.

 

Q7.   Write down any three points of atomic model proposed by Schrodinger or Bohr.

Or

Describe wave particle duality of electron of De Broglie Hypothesis? Prove that modern theory of De Broglie is related with Einstein and Plank's equations.

 

Q8.   Write down electronic configuration of ₅B, ₉F, ₇N, ₁₁Na, ₁₅P, ₂₀Ca, ₁₉K⁺, ₈O²⁻, ₁₆S²⁻, ₁₂Mg²⁺, ₁₇Cl⁻.

OR

Justify that Rutherford atomic model has defects? What are Limitations of Bohr's Atomic Model?

 

Q9.  Balance the any three of the following chemical equations:

             2KClO₃             → 2KCl      + 3O₂

             2Ba(NO₃)₂      →  2BaO  + 4NO₂  +  O₂

             2Na   + 2H₂O → 2NaOH + H₂

             2NH₃ + 3Cl₂  →  N₂ + 6HCl

             MnO₂ + 4HCl  → MnCl₂ + 2H₂O + Cl₂

             4NH₃  + 5O₂   → 4NO       +  6H₂O

4Zn + 10HNO₃  → 3H₂O+ NH₄NO₃    + 4Zn(NO₃)₂

3CuO      + 2NH₃ → 3Cu  +  N₂ + 3H₂O

OR

How is electronegative value determined the formation of chemical bond? Describe ionic character in covalent       bond.

 

Q10.    What is KMT? Give its main postulates with respect to three states of matter.

OR

What is diffusion and Graham’s law of diffusion of gases? Which gas from among CO₂, CH₄ and NH₃ will diffuse the fastest and why? Give the reason.

 

Q11.    Differentiate between amorphous and Crystalline Solids?

OR

Explain the solute-solvent interaction to prepare sodium chloride solution.

 

Q12.Define electrochemical reaction. Write down 2 differences between oxidation and reduction and oxidizing agent and reducing agent with examples. Identify oxidizing and reducing agents of the following chemical reaction:

              Zn + Cl₂ → ZnCl₂

OR

Differentiate between electrolytes and non-electrolytes with examples. Identify strong and weak electrolytes from the following:

HCl (S), KI (S), NaOH (S), H₂S (W), CH₃COOH (W), NH₄OH (W), NaCl (S), C₂H₅OH (W)

 

Q13. What is corrosion of metal and rusting? Name the methods which are used to protect metal from corrosion. How cathodic protection prevent metal from corrosion?

OR

Write down the composition of following alloys:

Brass (Cu-Zn,[4:1]), Bronze (Cu-Sn-Zn) [9:1], Bell metal (Cu-Sn), Monel (Ni-Cu-Fe), Amalgam (Hg-Ag-Cu-Zn), Pewter (Sn-Cu-Pb-Sb-Bi), White gold (Au-Pb-Ag-Cu (18 karat), Duralumin (Al-Cu-Mg-Ni)

 

Q14. What are metalloids? Write names and symbols of any 5 metalloids.

OR

Write names and symbols of some noble metals. Explain inertness of noble metals.

OR

Define Moh Scale. What are Soft & Hard Metals? Differentiate between sodium and iron as soft and hard metal.

 

Q15. What is the boiling point? How boiling point is affected by different factors? How boiling point of a substance is affected by atmospheric pressure?

            

Q16.    What is density, how the density of liquid is affected by temperature and pressure?

OR

What is plasma? Explain plasma with the daily life examples?

 

Q17. Describe the construction of electrochemical cell. Write down names of two types of electrochemical cells.   Write down 4 applications of electrolytic cells or electrolysis.

 

Q18.    Give reason:

(i) Why gasoline does not dissolve in water?

(ii) Alkali metals are not found in free state in nature, why?

(iii) Why ionic compounds conduct electricity in molten or in aqueous solutions only?

(iv) Why the solubility of a salt increases with the increase in temperature?

(v) Explain why table salt has a very high melting point.

(vi) Atomic radii increases down a group and decrease across a period.

(vii) Alkali metals have the largest while halogens have the smallest atomic radii in their period.

(viii) Shielding effect of inner electrons remains the same across a period.

 (ix) Ionization energy, electron affinity and electronegativity show same trends across a period.

(x) Covalent bonds are strong and hard to break but why most of the covalent compounds have low melting and boiling points. 

19.   Discuss Rutherford’s Alpha particles scattering experiment & write down the postulates of his atomic model.

         OR

Determine the demarcation of periodic table in to s, p, d and f blocks.

 

20.   Define ionic bond. Discuss the formation of sodium chloride (NaCl).

         OR

What is meant by covalent bond and coordinate covalent bond? Describe the formation of a covalent bond between two nonmetallic atoms. Explain single, double and triple covalent bond with examples. Explain dative bond with two examples.

 

21.   Describe the Boyle's law or Charles's law with example.

         OR

Define vapour pressure. How equilibrium state involved in vapour pressure of liquids in close system? Describe   the factors which affect on vapour pressure

 

22.   Define the term solubility. How does nature of solute and solvent determine the extent of dissolution? Why the solubility of a salt increases with the increase in temperature?

OR

Discuss discharge tube experiment for the discovery of electrons with 4 properties of cathode rays.

 

23.   State and explain Faraday’s Laws of electrolysis.

         OR

What is electroplating? How steel object can be electroplated with zinc and silver?

 

25.   Explain electronegative character of non-metals or electropositive character of metals. Discuss the reactivity of    Halogens

         OR

What are transition elements? Give their types. Give their 4 general properties.

 

26.   Explain the experiment to test CO₃^2‒, Cl^‒ and I^‒ ions and Zn²⁺, Mg²⁺, Ca²⁺ and Ba²⁺ ions.

 

Numericals

25.   Calculate the number of moles, number of molecules present in 8g of C₆H₁₂O₆? 

(answer; 0.04, 2.40 x 10²² molecules)

OR

Calculate the number of moles, number of molecules and number of atoms present in 10 g of H₂SO₄

 (answer; 0.10 mole, 6.02 x 1010²², 4.214 x 10²³ atoms)

 

26.   What is the mass of oxalic acid (C₂H₂O₄) required to prepare 100 cm³ volume of 2M oxalic acid solution?

         Or

What is the molarity of the solution prepared by dissolving 1.25 g of HCl gas into enough water to make 30 cm³ of solution?

 

27.   Determine the percentage concentration of the solution obtained by dissolving 10g sugar in 140g water

OR

A solution of 20 cm³ of alcohol is dissolved in 80cm³ of water. Calculate the concentration (v/v) of solution.

 

28.   10M HNO₃ solution is available in laboratory. How would you prepare 500 cm³ of 0.1M solution?

OR

A sample of sulphuric acid has the molarity 20M. How many cm³ of solution should you use to prepare 500 cm³ of 0.5M H₂SO₄? (Answer; 12.5cm³)

 

29.   The 800 cm³ of a gas is enclosed in a container under a pressure of 750 mm. If the volume is reduced to 250     cm³, what will be the pressure?

         OR

A sample of Hydrogen gas has a volume of 350 cm³ at 40 C. If gas is allowed to expand up to 700 cm³ at constant pressure. Find out its final temperature? (answer; 626 K)

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