Top 50 CBSE Class 12 Chemistry MCQs with Answers for High Score in Pre Board Exam 2026

Top 50 CBSE Class 12 Chemistry MCQs with Answers: CBSE Class 12 Chemistry is a crucial subject that requires strong conceptual clarity and regular practice to score well in the board examinations. To help students prepare effectively, this article provides the Top 50 CBSE Class 12 Chemistry MCQs for Pre-Board.

These multiple-choice questions are carefully prepared by taking reference from previous years’ CBSE Question Papers, sample papers, and the latest exam pattern. CBSE Class 12 Chemistry Exam 2026 is scheduled on 28 February 2026 (Saturday). The MCQs cover important topics from physical, organic, and inorganic chemistry, ensuring balanced revision of the syllabus. Practising these MCQs will help students improve accuracy, save time during the exam, and gain confidence for the CBSE Class 12 Exam 2026 for chemistry. 

Top 50 CBSE Class 12 Chemistry MCQs 

Q1. When MnO₂ is fused with KOH in presence of air, it forms:

(A) KMnO₄

(B) K₂MnO₄

(C) Mn₂O₇

(D) Mn₂O₃

Q2. EDTA⁴⁻ acts as a:

(A) Monodentate ligand

(B) Bidentate ligand

(C) Tridentate ligand

(D) Polydentate ligand

Q3. Which ligand forms a chelate complex?

(A) CO

(B) Cl⁻

(C) NH₃

(D) C₂O₄²⁻

Q4. Which compound contains sp² hybridised carbon bonded to X?

(A) CH₃–CH₂–X

(B) CH₂=CH–X

(C) CH₃–CH₂–CH₂–X

(D) CH₃–X

Q5. The most acidic compound among the following is:

(A) Phenol

(B) Ethanol

(C) Methanol

(D) Water

Q6. Anisole reacts with HI to give:

(A) Phenol + CH₃I

(B) Phenol + CH₃OH

(C) Iodobenzene

(D) Benzyl iodide

Q7. Ethanol heated with conc. H₂SO₄ at 413 K forms:

(A) Ethene

(B) Diethyl ether

(C) Ethyl hydrogen sulphate

(D) Acetaldehyde

Q8. An azeotropic mixture shows:

(A) No deviation from Raoult’s law

(B) Positive deviation

(C) Negative deviation

(D) Complete dissociation

Q9. If relative lowering of vapour pressure is 0.0225, mole fraction of solute is:

(A) 0.80

(B) 0.725

(C) 0.15

(D) 0.0225

Q10. During electrolysis of aqueous NaCl:

(A) H₂ is liberated at anode

(B) Na metal is formed at cathode

(C) Cl₂ gas is liberated at anode

(D) O₂ gas is liberated at cathode

Q11. Which first-row transition element has highest third ionisation enthalpy?

(A) Vanadium

(B) Chromium

(C) Manganese

(D) Iron

Q12. Which alcohol gives ketone on oxidation with CrO₃?

(A) Primary alcohol

(B) Secondary alcohol

(C) Tertiary alcohol

(D) Phenol

Q13. The third component of DNA is:

(A) Adenine

(B) Phosphoric acid

(C) Sulphuric acid

(D) Uracil

Q14. Van’t Hoff factor for association is:

(A) Greater than 1

(B) Equal to 1

(C) Less than 1

(D) Zero

Q15. For reaction X + 2Y → P, correct rate expression is:

(A) Rate = dP/dt

(B) Rate = –dX/dt

(C) Rate = –½ dY/dt

(D) All of these

Q16. Which compound undergoes SN1 reaction fastest?

(A) CH₃Cl

(B) CH₃CH₂Cl

(C) (CH₃)₃CCl

(D) C₆H₅Cl

Q17. Acetic acid reacts with PCl₅ to form:

(A) CH₃COCl

(B) CH₃Cl

(C) CH₃COOH

(D) CH₃COBr

Q18. Cannizzaro reaction occurs in:

(A) Aldehydes without α-hydrogen

(B) Ketones

(C) Carboxylic acids

(D) Alcohols

Q19. Half-life of zero-order reaction depends on:

(A) Initial concentration

(B) Temperature only

(C) Pressure only

(D) Catalyst only

Q20. Which shows linkage isomerism?

(A) [Co(NH₃)₆]Cl₃

(B) [Co(NH₃)₅NO₂]Cl₂

(C) K₄[Fe(CN)₆]

(D) [Cu(NH₃)₄]SO₄

Q21. Phosgene gas is formed by oxidation of:

(A) Methane

(B) Chloroform

(C) Benzene

(D) Ethanol

Q22. Denaturation of protein occurs in:

(A) Coagulation of egg white

(B) Curdling of milk

(C) Both A and B

(D) None

Q23. Which bond links nucleotides in DNA?

(A) Peptide bond

(B) Glycosidic bond

(C) Hydrogen bond

(D) Phosphodiester bond

Q24. Conversion of phenol to salicylic acid occurs by:

(A) Kolbe reaction

(B) Friedel–Crafts reaction

(C) Reimer–Tiemann reaction

(D) Cannizzaro reaction

Q25. Oxidation of secondary alcohol gives:

(A) Aldehyde

(B) Ketone

(C) Acid

(D) Ester

Q26. Which species is diamagnetic?

(A) [Ni(CN)₄]²⁻

(B) [Fe(CN)₆]³⁻

(C) [CoF₆]³⁻

(D) [NiCl₄]²⁻

Q27. Element with configuration [Ar] 3d¹⁰4s¹ is:

(A) Cu

(B) Zn

(C) Cr

(D) Mn

Q28. Order of reaction measures:

(A) Stoichiometry

(B) Molecularity

(C) Activation energy

(D) Rate law

Q29. Rate of zero-order reaction is:

(A) Constant

(B) Proportional to concentration

(C) Inversely proportional

(D) Zero

Q30. Reduction of 1 mol MnO₄⁻ to MnO₂ requires:

(A) 1 F

(B) 3 F

(C) 5 F

(D) 6 F

Q31. Alkyl halides undergoing SN2 reaction show:

(A) Racemisation

(B) Retention

(C) Inversion

(D) Rearrangement

Q32. Strongest acid among the following:

(A) Alcohol

(B) Phenol

(C) Carboxylic acid

(D) Water

Q33. Best reagent to convert amide to amine:

(A) Br₂ + NaOH

(B) LiAlH₄

(C) PCl₅

(D) H₂SO₄

Q34. Lanthanoid contraction is due to:

(A) Increase in atomic size

(B) Poor shielding of 4f electrons

(C) Increase in mass

(D) Extra electrons

Q35. Which compound gives iodoform test?

(A) Methanol

(B) Ethanol

(C) Propanol

(D) Phenol

Q36. Maximum oxidation state of Mn is:

(A) +5

(B) +6

(C) +7

(D) +4

Q37. Glucose does not give Schiff’s test because:

(A) It is ketose

(B) Aldehyde group is absent

(C) Aldehyde group is masked

(D) It is cyclic

Q38. Which reagent distinguishes aldehyde from ketone?

(A) Fehling’s solution

(B) Tollen’s reagent

(C) Benedict’s solution

(D) All of these

Q39. Which polymer is biodegradable?

(A) PVC

(B) Nylon-6,6

(C) PHBV

(D) Polythene

Q40. Which vitamin deficiency causes scurvy?

(A) Vitamin A

(B) Vitamin B₁

(C) Vitamin C

(D) Vitamin D

Q41. Primary structure of protein refers to:

(A) Folding

(B) α-helix

(C) Amino acid sequence

(D) Hydrogen bonding

Q42. Which solution shows maximum lowering of vapour pressure?

(A) 0.1 M glucose

(B) 0.1 M NaCl

(C) 0.1 M CaCl₂

(D) 0.1 M urea

Q43. Which compound shows optical isomerism?

(A) Butan-2-ol

(B) Ethanol

(C) Propanone

(D) Acetic acid

Q44. Which gas is released at anode during electrolysis of water?

(A) Hydrogen

(B) Oxygen

(C) Chlorine

(D) Nitrogen

Q45. Order of reactivity of alcohols with Lucas reagent:

(A) 1° > 2° > 3°

(B) 3° > 2° > 1°

(C) 2° > 3° > 1°

(D) Equal

Q46. Which catalyst is used in Haber process?

(A) Nickel

(B) Iron

(C) Platinum

(D) Vanadium

Q47. Which compound is used as antifreeze?

(A) Glycerol

(B) Ethanol

(C) Ethylene glycol

(D) Methanol

Q48. Which metal is extracted by electrolytic reduction?

(A) Iron

(B) Copper

(C) Aluminium

(D) Zinc

Q49. Which reaction converts alkene to alcohol?

(A) Ozonolysis

(B) Hydration

(C) Oxidation

(D) Dehydration

Q50. Which salt is used in photography?

(A) NaCl

(B) AgBr

(C) KNO₃

(D) CuSO₄

Top 50 CBSE Class 12 Chemistry MCQs Answers

Regular practice of MCQs is essential for scoring high in CBSE Class 12 Chemistry. These carefully selected questions strengthen conceptual understanding and exam readiness. Students are advised to revise these MCQs multiple times before the final board examination.

Also check:

CBSE Board Syllabus 2025-26

CBSE Class 12 Pre Board Sample Papers 2025-2026

CBSE Class 12 Biology Pre Board Sample Paper 2025-26 with Solutions