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CBSE Class 12 Chemistry Exam 2025-26: Top 50 Most Important MCQs with Answers for Last-Minute Revision
The CBSE Class 12 Chemistry exam is scheduled to be held on February 28, 2026. Section A of the exam is entirely MCQs (including Assertion-Reasoning), carrying a total of 16 marks. Therefore, MCQ preparation is crucial to securing a high score.
We have prepared the 50 most important MCQs with answers as per the latest CBSE syllabus 2025-26. These questions cover all major units, including Physical Chemistry (Solutions, Electrochemistry, Chemical Kinetics), Inorganic Chemistry (d & f Block, Coordination Compounds), and Organic Chemistry (Aldehydes, Amines, Biomolecules).
These questions are based on a competency-based and application-oriented pattern, focusing on conceptual clarity and numerical accuracy. Be sure to solve these 50 MCQs before the exam to boost your confidence. You can download the chapter-wise PDF from the table below to strengthen your preparation.
CBSE Class 12th Chemistry Exam Top 50 MCQs with Answers
Here are 50 important multiple-choice questions (MCQs) from all chapters in your 12th Chemistry syllabus along with their answers:
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. The value of Henry's constant KH is:
(A) Greater for gases with higher solubility
(B) Greater for gases with lower solubility
(C) Constant for all gases
(D) Not related to the nature of the gas
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. The hybridization of carbon in the carbonyl group is:
(A) sp (B) sp2 (C) sp3 (D) dsp2
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. Hoffmann Bromamide degradation is used to prepare:
(A) Secondary amines
(B) Primary amines
(C) Tertiary amines
(D) Quaternary salts
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 the Haber process?
(A) Nickel
(B) Iron
(C) Platinum
(D) Vanadium
Q47. HVZ reaction is used for the halogenation of:
(A) Alcohols
(B) Alkanes
(C) Carboxylic acids
(D) Ketones
Q48. Which test distinguishes between Methanal and Ethanal?
(A) Fehling's test
(B) Tollen's test
(C) Iodoform test
(D) Schiff's test
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
| Download PDF |
| CBSE Class 12 Chemistry Exam 2025-26 Top 50 Most Important MCQs with Answers PDF |
Top 50 CBSE Class 12 Chemistry MCQs Answers Key
| Question No. | Correct Answer |
| 1 | B |
| 2 | D |
| 3 | B |
| 4 | B |
| 5 | A |
| 6 | A |
| 7 | B |
| 8 | B |
| 9 | D |
| 10 | C |
| 11 | B |
| 12 | B |
| 13 | B |
| 14 | C |
| 15 | D |
| 16 | C |
| 17 | A |
| 18 | A |
| 19 | A |
| 20 | B |
| 21 | B |
| 22 | B |
| 23 | D |
| 24 | A |
| 25 | B |
| 26 | A |
| 27 | A |
| 28 | B |
| 29 | A |
| 30 | B |
| 31 | B |
| 32 | C |
| 33 | A |
| 34 | B |
| 35 | B |
| 36 | C |
| 37 | C |
| 38 | B |
| 39 | C |
| 40 | C |
| 41 | C |
| 42 | C |
| 43 | A |
| 44 | B |
| 45 | B |
| 46 | B |
| 47 | C |
| 48 | C |
| 49 | B |
| 50 | B |
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👉 CBSE Class 12 Study Materials
CBSE Class 12 study material includes latest syllabus, sample papers, NCERT books and solutions, previous year question papers, chapter-wise important questions, case study questions, assertion-reason questions, and competency-based questions — all updated as per the latest CBSE board exam pattern.
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