CBSE Class 12 Previous Year Chemistry MCQs

CBSE Class 12 Previous Year Chemistry MCQs

CBSE 12th Exam: 2025

Q1: Which is the correct order of acid strength from the following?

1. C₆H₅OH > H₂O > ROH
2. C₆H₅OH > ROH > H₂O
3. ROH > C₆H₅OH > H₂O
4. H₂O > C₆H₅OH > ROH

Correct Answer: A

Phenol forms a stable phenoxide ion, making it more acidic than water and alcohols.

CBSE 12th Exam: 2024

Q2: Which of the following has the highest boiling point?

1. CH₃OH
2. CH₃CH₂OH
3. CH₃OCH₃
4. CH₃CH₂CH₂OH

Correct Answer: D

More carbons increase van der Waals forces; propanol has stronger intermolecular forces.

CBSE 12th Exam: 2023

Q3: Which reagent is used to distinguish aldehydes from ketones?

1. Tollens’ reagent
2. Fehling’s solution
3. Benedict’s solution
4. All of the above

Correct Answer: D

Aldehydes reduce Tollens’, Fehling’s, and Benedict’s solutions, while ketones generally do not.

CBSE 12th Exam: 2025

Q4: Which of the following has the maximum ionic character?

1. NaCl
2. KCl
3. MgCl₂
4. CaCl₂

Correct Answer: B

KCl has the largest difference in electronegativity and least polarization, giving maximum ionic character.

CBSE 12th Exam: 2022

Q5: Which of the following is a secondary alcohol?

1. CH₃CH₂OH
2. CH₃CHOHCH₃
3. CH₃OH
4. (CH₃)₃COH

Correct Answer: B

Isopropanol has the –OH group attached to a carbon bonded to two other carbons, making it secondary.

CBSE 12th Exam: 2021

Q6: Which of the following is most reactive towards electrophilic substitution?

1. Benzene
2. Toluene
3. Nitrobenzene
4. Chlorobenzene

Correct Answer: B

Toluene has an electron-donating methyl group, activating the ring towards electrophilic substitution.

CBSE 12th Exam: 2025

Q7: Which of the following is used in the manufacture of soaps?

1. Saponification
2. Esterification
3. Hydrogenation
4. Polymerization

Correct Answer: A

Saponification of fats/oils with alkali produces soap and glycerol.

CBSE 12th Exam: 2024

Q8: Which of the following is an example of a condensation polymer?

1. Polyethylene
2. Polystyrene
3. Nylon-6,6
4. Polypropene

Correct Answer: C

Nylon-6,6 is formed by condensation of adipic acid and hexamethylenediamine.

CBSE 12th Exam: 2023

Q9: Which of the following is used as an anti-knock compound in petrol?

1. Tetraethyl lead
2. Benzene
3. Toluene
4. Iso-octane

Correct Answer: A

Tetraethyl lead was historically used to reduce knocking in petrol engines.

CBSE 12th Exam: 2022

Q10: Which of the following is a greenhouse gas?

1. CO₂
2. O₂
3. N₂
4. Ar

Correct Answer: A

Carbon dioxide traps heat in the atmosphere, contributing to the greenhouse effect.

CBSE 12th Exam: 2021

Q11: Which of the following is an example of a heterogeneous catalyst?

1. Pt in hydrogenation of alkenes
2. H₂SO₄ in esterification
3. AlCl₃ in Friedel–Crafts reaction
4. Both A and C

Correct Answer: D

Pt and AlCl₃ act as solid catalysts in reactions with gaseous/liquid reactants.

CBSE 12th Exam: 2022

Q12: Which of the following is the correct order of basicity?

1. NH₃ > CH₃NH₂ > (CH₃)₂NH
2. (CH₃)₂NH > CH₃NH₂ > NH₃
3. NH₃ > (CH₃)₂NH > CH₃NH₂
4. CH₃NH₂ > NH₃ > (CH₃)₂NH

Correct Answer: B

Alkyl groups increase electron density on nitrogen, enhancing basicity.

CBSE 12th Exam: 2023

Q13: Which of the following is used in the silvering of mirrors?

1. AgNO₃
2. Tollens’ reagent
3. Fehling’s solution
4. CuSO₄

Correct Answer: B

Tollens’ reagent deposits metallic silver on glass surfaces, used in mirror making.

CBSE 12th Exam: 2024

Q14: Which of the following is an example of a reducing sugar?

1. Sucrose
2. Glucose
3. Starch
4. Cellulose

Correct Answer: B

Glucose has a free aldehyde group in solution, making it a reducing sugar.

CBSE 12th Exam: 2025

Q15: Which of the following has the highest conductivity?

1. 0.1 M NaCl
2. 0.1 M CH₃COOH
3. 0.1 M NH₃
4. 0.1 M glucose

Correct Answer: A

NaCl is a strong electrolyte, fully ionizing in water, giving maximum conductivity.

CBSE 12th Exam: 2022

Q16: Which of the following is used in the manufacture of ammonia?

1. Haber process
2. Ostwald process
3. Contact process
4. Solvay process

Correct Answer: A

The Haber process synthesizes ammonia from nitrogen and hydrogen under high pressure and temperature.

CBSE 12th Exam: 2023

Q17: Which of the following is used as a moderator in nuclear reactors?

1. Graphite
2. Heavy water
3. Boron rods
4. Both A and B

Correct Answer: D

Graphite and heavy water slow down neutrons, acting as moderators in reactors.

CBSE 12th Exam: 2024

Q18: Which of the following is an example of a coordination compound?

1. NaCl
2. K₂SO₄
3. [Cu(NH₃)₄]SO₄
4. CaCO₃

Correct Answer: C

[Cu(NH₃)₄]SO₄ is a coordination compound with ligands bonded to a central metal ion.

CBSE 12th Exam: 2025

Q19: Which of the following is used in the preparation of mustard gas?

1. Ethylene
2. Chlorine
3. Both A and B
4. None of these

Correct Answer: C

Mustard gas is prepared by reacting ethylene with chlorine.

CBSE 12th Exam: 2021

Q20: Which of the following is used in the vulcanization of rubber?

1. Sulphur
2. Phosphorus
3. Carbon
4. Silicon

Correct Answer: A

Sulphur cross-links rubber chains, improving elasticity and strength.

CBSE 12th Exam: 2022

Q21: Which of the following is used in the manufacture of nitric acid?

1. Haber process
2. Ostwald process
3. Contact process
4. Solvay process

Correct Answer: B

The Ostwald process oxidizes ammonia to nitric acid using platinum catalyst.

CBSE 12th Exam: 2023

Q22: Which of the following is a biodegradable polymer?

1. Polyethylene
2. Polystyrene
3. PHBV
4. PVC

Correct Answer: C

PHBV (polyhydroxybutyrate-co-valerate) is a biodegradable polymer.

CBSE 12th Exam: 2024

Q23: Which of the following is used as an anesthetic?

1. CHCl₃
2. CH₃OH
3. CH₃COOH
4. CH₃CHO

Correct Answer: A

Chloroform was historically used as an anesthetic.

CBSE 12th Exam: 2025

Q24: Which of the following is used in the preparation of glass?

1. Na₂CO₃
2. CaCO₃
3. SiO₂
4. All of the above

Correct Answer: D

Glass is made by fusing silica with sodium carbonate and calcium carbonate.

CBSE 12th Exam: 2021

Q25: Which of the following is used in the preparation of nylon?

1. Adipic acid
2. Hexamethylenediamine
3. Both A and B
4. None of these

Correct Answer: C

Nylon-6,6 is prepared by condensation of adipic acid and hexamethylenediamine.

CBSE 12th Exam: 2022

Q26: Which of the following is used in the preparation of bleaching powder?

1. Cl₂
2. Ca(OH)₂
3. Both A and B
4. None of these

Correct Answer: C

Bleaching powder is prepared by passing chlorine gas over dry slaked lime.

CBSE 12th Exam: 2023

Q27: Which of the following is used in the preparation of Portland cement?

1. CaCO₃
2. SiO₂
3. Al₂O₃
4. All of the above

Correct Answer: D

Portland cement is made from limestone, clay, and gypsum containing CaCO₃, SiO₂, and Al₂O₃.

CBSE 12th Exam: 2024

Q28: Which of the following is used in the preparation of artificial silk?

1. Cellulose
2. Rayon
3. Both A and B
4. Nylon

Correct Answer: C

Artificial silk (rayon) is prepared from cellulose.

CBSE 12th Exam: 2025

Q29: Which of the following is used in the preparation of baking soda?

1. NaCl
2. NH₃
3. CO₂
4. All of the above

Correct Answer: D

Baking soda is prepared in the Solvay process using NaCl, NH₃, and CO₂.

CBSE 12th Exam: 2021

Q30: Which of the following is used in the preparation of washing soda?

1. Na₂CO₃
2. NaCl
3. NH₃
4. CO₂

Correct Answer: A

Washing soda is hydrated sodium carbonate (Na₂CO₃·10H₂O).

CBSE 12th Exam: 2022

Q31: Which of the following is used in the preparation of chloroform?

1. CH₃OH
2. CH₃COOH
3. CH₃CHO
4. CH₃OH + Cl₂

Correct Answer: D

Chloroform is prepared by chlorination of methanol.

CBSE 12th Exam: 2023

Q32: Which of the following is used in the preparation of vinegar?

1. CH₃OH
2. CH₃CHO
3. CH₃COOH
4. CH₃CH₂OH

Correct Answer: C

Vinegar is dilute acetic acid (CH₃COOH).

CBSE 12th Exam: 2024

Q33: Which of the following is used in the preparation of formalin?

1. CH₃OH
2. HCHO
3. CH₃COOH
4. CH₃CHO

Correct Answer: B

Formalin is a 40% aqueous solution of formaldehyde (HCHO).

CBSE 12th Exam: 2025

Q34: Which of the following is used in the preparation of urea?

1. NH₃
2. CO₂
3. Both A and B
4. None of these

Correct Answer: C

Urea is prepared by reacting ammonia with carbon dioxide.

CBSE 12th Exam: 2021

Q35: Which of the following is used in the preparation of nylon-6?

1. Caprolactam
2. Adipic acid
3. Hexamethylenediamine
4. None of these

Correct Answer: A

Nylon-6 is prepared by polymerization of caprolactam.

CBSE 12th Exam: 2022

Q36: Which of the following is used in the preparation of Teflon?

1. CF₂=CF₂
2. CH₂=CH₂
3. CCl₂=CCl₂
4. CH₃CH=CH₂

Correct Answer: A

Teflon is polytetrafluoroethylene, formed from CF₂=CF₂.

CBSE 12th Exam: 2023

Q37: Which of the following is used in the preparation of PVC?

1. CH₂=CHCl
2. CH₂=CH₂
3. CH₃CH=CH₂
4. CF₂=CF₂

Correct Answer: A

PVC is polyvinyl chloride, formed from vinyl chloride monomer (CH₂=CHCl).

CBSE 12th Exam: 2024

Q38: Which of the following is used in the preparation of Bakelite?

1. Phenol
2. Formaldehyde
3. Both A and B
4. None of these

Correct Answer: C

Bakelite is a condensation polymer of phenol and formaldehyde.

CBSE 12th Exam: 2025

Q39: Which of the following is used in the preparation of DDT?

1. Chlorobenzene
2. Trichloroacetaldehyde
3. Both A and B
4. None of these

Correct Answer: C

DDT is prepared by condensation of chlorobenzene with trichloroacetaldehyde.

CBSE 12th Exam: 2021

Q40: Which of the following is used in the preparation of TNT?

1. Toluene
2. Phenol
3. Benzene
4. Chlorobenzene

Correct Answer: A

TNT (trinitrotoluene) is prepared by nitration of toluene.

CBSE 12th Exam: 2022

Q41: Which of the following is used in the preparation of aspirin?

1. Salicylic acid
2. Acetic anhydride
3. Both A and B
4. Phenol

Correct Answer: C

Aspirin is prepared by acetylation of salicylic acid with acetic anhydride.

CBSE 12th Exam: 2023

Q42: Which of the following is used in the preparation of soap?

1. Fatty acids
2. NaOH
3. Both A and B
4. Glycerol

Correct Answer: C

Soap is prepared by saponification of fatty acids with sodium hydroxide.

CBSE 12th Exam: 2024

Q43: Which of the following is used in the preparation of biodiesel?

1. Vegetable oil
2. Methanol
3. Both A and B
4. Petroleum

Correct Answer: C

Biodiesel is prepared by transesterification of vegetable oils with methanol.

CBSE 12th Exam: 2025

Q44: Which of the following is used in the preparation of ethanol industrially?

1. Fermentation of sugars
2. Hydration of ethene
3. Both A and B
4. None of these

Correct Answer: C

Ethanol is produced by fermentation of sugars and also by hydration of ethene.

CBSE 12th Exam: 2021

Q45: Which of the following is used in the preparation of ethylene glycol?

1. Ethene
2. Ethylene oxide
3. Both A and B
4. None of these

Correct Answer: B

Ethylene glycol is prepared by hydrolysis of ethylene oxide.

CBSE 12th Exam: 2022

Q46: Which of the following is used in the preparation of phenol?

1. Cumene
2. Benzene
3. Toluene
4. Chlorobenzene

Correct Answer: A

Phenol is industrially prepared from cumene via cumene hydroperoxide process.

CBSE 12th Exam: 2023

Q47: Which of the following is used in the preparation of aniline?

1. Nitrobenzene
2. Benzene
3. Toluene
4. Phenol

Correct Answer: A

Aniline is prepared by reduction of nitrobenzene.

CBSE 12th Exam: 2024

Q48: Which of the following is used in the preparation of acetic acid industrially?

1. Methanol
2. Carbon monoxide
3. Both A and B
4. Ethene

Correct Answer: C

Acetic acid is prepared by carbonylation of methanol with carbon monoxide.

CBSE 12th Exam: 2025

Q49: Which of the following is used in the preparation of acetone?

1. Isopropanol
2. Propene
3. Both A and B
4. None of these

Correct Answer: A

Acetone is prepared by oxidation of isopropanol.

CBSE 12th Exam: 2021

Q50: Which of the following is used in the preparation of ethyl acetate?

1. CH₃COOH + C₂H₅OH
2. CH₃CHO + C₂H₅OH
3. CH₃OH + CH₃COOH
4. CH₃OH + CH₃CHO

Correct Answer: A

Ethyl acetate is prepared by esterification of acetic acid with ethanol.

CBSE 12th Exam: 2022

Q51: Which of the following is used in the preparation of nylon-6,6?

1. Adipic acid + Hexamethylenediamine
2. Caprolactam
3. Phenol + Formaldehyde
4. Vinyl chloride

Correct Answer: A

Nylon-6,6 is formed by condensation of adipic acid and hexamethylenediamine.

CBSE 12th Exam: 2023

Q52: Which of the following is used in the preparation of silicones?

1. CH₃SiCl₃
2. SiCl₄
3. Both A and B
4. SiO₂

Correct Answer: C

Silicones are prepared by hydrolysis and polymerization of organosilicon chlorides.

CBSE 12th Exam: 2024

Q53: Which of the following is used in the preparation of rayon?

1. Cellulose
2. Caprolactam
3. Adipic acid
4. Vinyl chloride

Correct Answer: A

Rayon is regenerated cellulose, used as artificial silk.

CBSE 12th Exam: 2025

Q54: Which of the following is used in the preparation of glyptal resin?

1. Phthalic acid + Glycerol
2. Phenol + Formaldehyde
3. Adipic acid + Hexamethylenediamine
4. Caprolactam

Correct Answer: A

Glyptal resin is formed by condensation of phthalic acid and glycerol.

CBSE 12th Exam: 2021

Q55: Which of the following is used in the preparation of polyethene?

1. Ethene
2. Propene
3. Vinyl chloride
4. Styrene

Correct Answer: A

Polyethene is formed by polymerization of ethene.

CBSE 12th Exam: 2022

Q56: Which of the following is used in the preparation of polystyrene?

1. Styrene
2. Ethene
3. Propene
4. Vinyl chloride

Correct Answer: A

Polystyrene is formed by polymerization of styrene monomer.

CBSE 12th Exam: 2023

Q57: Which of the following is used in the preparation of polyvinyl alcohol?

1. Vinyl acetate
2. Vinyl chloride
3. Ethene
4. Propene

Correct Answer: A

Polyvinyl alcohol is prepared by hydrolysis of polyvinyl acetate.

CBSE 12th Exam: 2024

Q58: Which of the following is used in the preparation of polyacrylonitrile?

1. Acrylonitrile
2. Vinyl chloride
3. Styrene
4. Ethene

Correct Answer: A

Polyacrylonitrile is formed by polymerization of acrylonitrile monomer.

CBSE 12th Exam: 2025

Q59: Which of the following is used in the preparation of polyester (Terylene)?

1. Terephthalic acid + Ethylene glycol
2. Adipic acid + Hexamethylenediamine
3. Phenol + Formaldehyde
4. Caprolactam

Correct Answer: A

Polyester (Terylene) is formed by condensation of terephthalic acid and ethylene glycol.

CBSE 12th Exam: 2021

Q60: Which of the following is used in the preparation of polycarbonate?

1. Bisphenol-A + Phosgene
2. Phenol + Formaldehyde
3. Adipic acid + Hexamethylenediamine
4. Caprolactam

Correct Answer: A

Polycarbonate is formed by condensation of bisphenol-A with phosgene.

CBSE 12th Exam: 2022

Q61: Which of the following is used in the preparation of nylon-2, nylon-6 (protein-based polymer)?

1. Glycine + Amino caproic acid
2. Adipic acid + Hexamethylenediamine
3. Caprolactam
4. Phenol + Formaldehyde

Correct Answer: A

Nylon-2,6 is a copolymer of glycine and amino caproic acid.

CBSE 12th Exam: 2023

Q62: Which of the following is used in the preparation of Kevlar?

1. Terephthalic acid + p-phenylenediamine
2. Adipic acid + Hexamethylenediamine
3. Caprolactam
4. Phenol + Formaldehyde

Correct Answer: A

Kevlar is a polyamide formed from terephthalic acid and p-phenylenediamine.

CBSE 12th Exam: 2024

Q63: Which of the following is used in the preparation of Buna-S rubber?

1. Butadiene + Styrene
2. Butadiene + Acrylonitrile
3. Isoprene
4. Vinyl chloride

Correct Answer: A

Buna-S is a copolymer of butadiene and styrene.

CBSE 12th Exam: 2025

Q64: Which of the following is used in the preparation of Buna-N rubber?

1. Butadiene + Acrylonitrile
2. Butadiene + Styrene
3. Isoprene
4. Vinyl chloride

Correct Answer: A

Buna-N is a copolymer of butadiene and acrylonitrile.

CBSE 12th Exam: 2021

Q65: Which of the following is used in the preparation of neoprene rubber?

1. Chloroprene
2. Butadiene
3. Isoprene
4. Styrene

Correct Answer: A

Neoprene is formed by polymerization of chloroprene.

CBSE 12th Exam: 2022

Q66: Which of the following is used in the preparation of natural rubber?

1. Isoprene
2. Butadiene
3. Styrene
4. Vinyl chloride

Correct Answer: A

Natural rubber is cis-1,4-polyisoprene.

CBSE 12th Exam: 2023

Q67: Which of the following is used in the preparation of Lexan (polycarbonate)?

1. Bisphenol-A + Phosgene
2. Phenol + Formaldehyde
3. Caprolactam
4. Adipic acid + Hexamethylenediamine

Correct Answer: A

Lexan is a polycarbonate formed from bisphenol-A and phosgene.

CBSE 12th Exam: 2024

Q68: Which of the following is used in the preparation of glyptal paint?

1. Phthalic acid + Glycerol
2. Phenol + Formaldehyde
3. Caprolactam
4. Vinyl chloride

Correct Answer: A

Glyptal paint is based on glyptal resin from phthalic acid and glycerol.

CBSE 12th Exam: 2025

Q69: Which of the following is used in the preparation of bakelite?

1. Phenol + Formaldehyde
2. Adipic acid + Hexamethylenediamine
3. Caprolactam
4. Vinyl chloride

Correct Answer: A

Bakelite is a condensation polymer of phenol and formaldehyde.

CBSE 12th Exam: 2021

Q70: Which of the following is used in the preparation of melamine-formaldehyde resin?

1. Melamine + Formaldehyde
2. Phenol + Formaldehyde
3. Urea + Formaldehyde
4. Caprolactam

Correct Answer: A

Melamine-formaldehyde resin is formed by condensation of melamine with formaldehyde.

CBSE 12th Exam: 2022

Q71: Which of the following is used in the preparation of urea-formaldehyde resin?

1. Urea + Formaldehyde
2. Phenol + Formaldehyde
3. Melamine + Formaldehyde
4. Caprolactam

Correct Answer: A

Urea-formaldehyde resin is formed by condensation of urea with formaldehyde.

CBSE 12th Exam: 2023

Q72: Which of the following is used in the preparation of polyvinylidene chloride?

1. CH₂=CCl₂
2. CH₂=CHCl
3. CH₂=CH₂
4. CH₃CH=CH₂

Correct Answer: A

Polyvinylidene chloride is formed by polymerization of vinylidene chloride monomer (CH₂=CCl₂).

CBSE 12th Exam: 2024

Q73: Which of the following is used in the preparation of Terylene (polyester)?

1. Terephthalic acid + Ethylene glycol
2. Adipic acid + Hexamethylenediamine
3. Phenol + Formaldehyde
4. Caprolactam

Correct Answer: A

Terylene is a polyester formed by condensation of terephthalic acid and ethylene glycol.

CBSE 12th Exam: 2025

Q74: Which of the following is used in the preparation of Novolac resin?

1. Phenol + Formaldehyde (acidic medium)
2. Phenol + Formaldehyde (basic medium)
3. Urea + Formaldehyde
4. Melamine + Formaldehyde

Correct Answer: A

Novolac resin is formed by condensation of phenol and formaldehyde in acidic medium.

CBSE 12th Exam: 2021

Q75: Which of the following is used in the preparation of Glyptal resin (alkyd resin)?

1. Phthalic acid + Glycerol
2. Phenol + Formaldehyde
3. Adipic acid + Hexamethylenediamine
4. Caprolactam

Correct Answer: A

Glyptal resin (alkyd resin) is formed by condensation of phthalic acid and glycerol.