🔎 Complete Karachi Board Chemistry Paper MCQ Collection + Model Paper 2023/2024/2025! 💡

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🌟 Your Ultimate Karachi Board Chemistry MCQs & Model Paper Guide for 2024/2025 🔬📈

🚀 Unlock Chemistry Success with Karachi Board MCQs 2024! 🔬

📦 Q1. The colour of flame produced by Beryllium is

🟥 (a) Red

🟨 (b) No colour 

🟦 (c) Silver white

🟩 (d) Deep red

📦 Q2. The reason that benzene burns with soot is

🟨 (a) Inflammability

🟧 (b) Higher carbon content 

🟪 (c) High resonance energy

🟩 (d) Aromaticity

📦 Q3. Drugs that make body temperature normal are called

🟦 (a) Antibiotic

🟥 (b) Antipyretic 

🟩 (c) Antiallergic

🟨 (d) Antihistamine

📦 Q4. This process is used to improve octane number of gasoline

🟩 (a) Reforming 

🟦 (b) Refining

🟥 (c) Distillation

🟨 (d) Condensation

📦 Q5. The general formula of nitrides for alkaline earth metals is

🟧 (a) MN₃

🟦 (b) M₂N₃

🟥 (c) M₃N

🟩 (d) M₃N₂ 

📦 Q6. Formic acid is naturally found in

🟨 (a) Apple

🟥 (b) Bee’s sting 

🟩 (c) Vinegar

🟦 (d) Butter

📦 Q7. An example of thermoplastic is

🟩 (a) Polythene 

🟦 (b) Nylon

🟥 (c) PVC

🟨 (d) Bakelite

📦 Q8. The general formula for cycloalkane is:

🟩 (a) CₙH₂ₙ 

🟥 (b) CₙH₂ₙ₊₂

🟦 (c) CₙH₂ₙ₋₂

🟨 (d) CₙH₄ₙ

📦 Q9. NMR spectroscopy is concerned with the interaction of molecules with:

🟥 (a) Infrared radiation

🟦 (b) Visible radiation

🟩 (c) Ultraviolet radiation

🟨 (d) Radio waves 

📦 Q10. Oxidation state of manganese in KMnO₄ (potassium permanganate) is:

🟦 (a) +4

🟥 (b) +2

🟩 (c) +7 

🟨 (d) +5

📦 Q11. The greenhouse gas is:

🟥 (a) O₂

🟦 (b) N₂

🟩 (c) Ar

🟨 (d) CO₂ 

📦 Q12. The extra glucose of bloodstream is converted into:

🟥 (a) Fat

🟦 (b) Glycogen 

🟩 (c) Gluconic acid

🟨 (d) Triglyceride

📦 Q13. Beryllium is diagonally related to this:

🟥 (a) Li

🟦 (b) Si

🟩 (c) Al 

🟨 (d) Mg

📦 Q14. On oxidation, a secondary alcohol gives:

🟥 (a) Ether

🟦 (b) Aldehyde

🟩 (c) Ketone 

🟨 (d) Amine

📦 Q15. The coordination number of cobalt in Na₄[Co(C₂O₄)₃] is:

🟥 (a) 3

🟦 (b) 4

🟩 (c) 6 

🟨 (d) 2

📦 Q16. This element is not used in electroplating:

🟥 (a) Zn

🟦 (b) Sn

🟩 (c) Cr

🟨 (d) Mn 

📦 Q17. Ozone depletion in upper atmosphere is mainly caused by:

🟥 (a) SO₂

🟦 (b) NO

🟩 (c) CO

🟨 (d) CFC 

✅ Answer Key & Short Reasons

🟦🔳1. No colour — Be does not impart flame colour.
🟦🔳2. Higher carbon content — Benzene’s high C:H ratio causes sooty flame.
🟦🔳3. Antipyretic — These drugs reduce fever.
🟦🔳4. Reforming — Rearranges hydrocarbons to raise octane number.
🟦🔳5. M₃N₂ — Alkaline earth metals (M²⁺) + N³⁻ → M₃N₂.
🟦🔳6. Bee’s sting — Formic acid occurs in ants and bees.
🟦🔳7. Polythene — A common thermoplastic.
🟦🔳8. CₙH₂ₙ — Cycloalkanes follow this formula.
🟦🔳9. Radio waves — NMR uses radio frequency in magnetic fields.
🟦🔳10. +7 — Mn in KMnO₄ is in +7 oxidation state.
🟦🔳11. CO₂ — Major greenhouse gas trapping heat in Earth’s atmosphere.
🟦🔳12. Glycogen — Extra glucose is stored in liver/muscles as glycogen.
🟦🔳13. Aluminium (Al) — Beryllium shows diagonal relationship with Al in periodic table.
🟦🔳14. Ketone — Secondary alcohols oxidize to ketones.
🟦🔳15. 6 — Each oxalate is bidentate; 3 ligands → coordination number 6.
🟦🔳16. Manganese (Mn) — Not commonly used for electroplating unlike Zn, Sn, Cr.
🟦🔳17. CFCs — Chlorofluorocarbons release chlorine radicals that destroy ozone.

🔥 💥 Get Ready for Karachi Board Chemistry with Top Viral MCQs Model Paper MCQs 2023 🔥 📚

📦 Q1. The oxidation states of the elements of group VA:

🟥 (a) +1 and +3

🟦 (b) –3 and –5

🟩 (c) –3, +3 and +5 ✅

🟨 (d) +1, –1 and +3

📦 Q2. Which of the following s-block element forms superoxide when burned in air:

🟥 (a) Li

🟦 (b) Na

🟩 (c) K ✅

🟨 (d) Mg

📦 Q3. In the equilibrium of dichromate–chromate ion the colour of CrO₄²⁻ is:

🟥 (a) Orange

🟦 (b) Green

🟩 (c) Yellow ✅

🟨 (d) Red

📦 Q4. The coordination number of cobalt in Na₃[Co(C₂O₄)₃] is:

🟥 (a) 3

🟦 (b) 4

🟩 (c) 6 ✅

🟨 (d) 7

📦 Q5. The knocking of internal combustion engine can be reduced by the following petroleum process:

🟥 (a) Reforming ✅

🟦 (b) Refining

🟩 (c) Distillation

🟨 (d) Condensation

📦 Q6. How many optical isomers are possible for HOOC–CH(OH)–CH(Br)–COOH:

🟥 (a) 2

🟦 (b) 3

🟩 (c) 4 ✅

🟨 (d) 5

📦 Q7. Which of the following pairs of compounds represent functional group isomerism:

🟥 (a) 1-butene and 2-butene

🟦 (b) Ethanol and dimethyl ether ✅

🟩 (c) n-butane and iso-butane

🟨 (d) Diethyl ketone and methyl propyl ketone

📦 Q8. Benzene burns with smoky flame because of its:

🟥 (a) High resonance energy

🟦 (b) High carbon % ✅

🟩 (c) Inflammability

🟨 (d) Aromaticity

📦 Q9. The kinetics of elimination bimolecular reaction is:

🟥 (a) Zero order

🟦 (b) First order

🟩 (c) Second order ✅

🟨 (d) Third order

📦 Q10. Lucas reagent is a mixture of:

🟥 (a) Zn and Hg

🟦 (b) Zn and HCl

🟩 (c) ZnCl₂ and HCl ✅

🟨 (d) NaOH and CaO

📦 Q11. Clemmensen reduction is the conversion of aldehydes and ketones into:

🟥 (a) Alkanes ✅

🟦 (b) Alkenes

🟩 (c) Alkyl halides

🟨 (d) Alcohols

📦 Q12. Formic acid is naturally found in:

🟥 (a) Valerian root

🟦 (b) Bee’s sting ✅

🟩 (c) Vinegar

🟨 (d) Butter

📦 Q13. An example of quaternary structure of protein is:

🟥 (a) Myoglobin

🟦 (b) Hemoglobin ✅

🟩 (c) Albumin

🟨 (d) Globulin

📦 Q14. Drugs that lower the body temperature to normal are known as:

🟥 (a) Antibiotics

🟦 (b) Antipyretic ✅

🟩 (c) Antiallergic

🟨 (d) Antihistamines

📦 Q15. An example of thermosetting plastic is:

🟥 (a) Polyethene

🟦 (b) PVC

🟩 (c) Nylon

🟨 (d) Bakelite ✅

📦 Q16. The region of sphere which extends from 11 km to 50 km from Earth is known as:

🟥 (a) Troposphere

🟦 (b) Stratosphere ✅

🟩 (c) Mesosphere

🟨 (d) Thermosphere

📦 Q17. Infrared spectroscopy is a technique used to determine:

🟥 (a) Double and triple bonds

🟦 (b) Functional group ✅

🟩 (c) Mass-to-charge ratio

🟨 (d) Conjugated system

✅ Answer Key & Short Reasons

🟦🔳1. –3, +3, +5 — Group VA elements show these common oxidation states.

🟦🔳2. K — Potassium forms KO₂ (superoxide).

🟦🔳3. Yellow — Chromate ions (CrO₄²⁻) are yellow.

🟦🔳4. 6 — Three oxalates, each bidentate → coordination number 6.

🟦🔳5. Reforming — Improves octane number, reduces knocking.

🟦🔳6. 4 — Two chiral centers → 2² = 4 optical isomers.

🟦🔳7. Ethanol & dimethyl ether — Same formula, different functional groups.

🟦🔳8. High carbon % — Benzene’s high C:H ratio causes smoky flame.

🟦🔳9. Second order — E₂ elimination follows bimolecular kinetics.

🟦🔳10. ZnCl₂ + HCl — Lucas reagent for alcohol classification.

🟦🔳11. Alkanes — Clemmensen reduction converts carbonyls to alkanes.

🟦🔳12. Bee’s sting — Formic acid occurs naturally in ants/bees.

🟦🔳13. Hemoglobin — Quaternary structure with multiple polypeptide chains.

🟦🔳14. Antipyretic — Drugs that reduce fever.

🟦🔳15. Bakelite — Classic thermosetting plastic.

🟦🔳16. Stratosphere — Lies between 11–50 km altitude.

🟦🔳17. Functional groups — IR spectroscopy identifies functional groups by absorption bands.