CBSE Class 12 Chemistry Practice MCQs for Board Preparation
CBSE Class 12 Chemistry Practice MCQs for Board Preparation (NCERT Based)
Course: CBSE Class 12 Chemistry
Section: Exam-Focused MCQs for CBSE Class 12 Chemistry
This 50-question MCQ practice set is strictly aligned with the NCERT Class 12 Chemistry syllabus and designed for systematic board exam preparation. The questions reflect frequently tested concepts, reactions, formulas, trends, and applications in CBSE board exams.
Each MCQ includes the correct answer with a clear, concept-clearing explanation and is arranged section-wise for balanced revision.
Section A: Physical Chemistry (Practice MCQs)
Q1. Raoult’s law is applicable to
(a) Ideal solutions
(b) Non-ideal solutions
(c) Colloidal solutions
(d) Electrolytic solutions
Answer: (a)
Explanation: Raoult’s law is valid for ideal solutions where intermolecular forces between components are similar.
Q2. Molality is preferred over molarity for colligative properties because it
(a) Depends on volume
(b) Is temperature independent
(c) Is easier to calculate
(d) Uses litres of solution
Answer: (b)
Explanation: Molality depends on mass of solvent, which does not change with temperature.
Q3. The van’t Hoff factor for AlCl₃ in aqueous solution is
(a) 1
(b) 2
(c) 3
(d) 4
Answer: (d)
Explanation: AlCl₃ dissociates into Al³⁺ + 3Cl⁻ ions, giving four particles.
Q4. EMF of a galvanic cell is maximum when
(a) Current flows
(b) Reaction is at equilibrium
(c) No current flows
(d) Resistance is minimum
Answer: (c)
Explanation: EMF is measured under open-circuit conditions.
Q5. Half-life of a first-order reaction depends on
(a) Initial concentration
(b) Rate constant
(c) Pressure
(d) Time
Answer: (b)
Explanation: ( t_{1/2} = \frac{0.693}{k} ).
Q6. Unit of rate constant for a zero-order reaction is
(a) s⁻¹
(b) mol L⁻¹ s⁻¹
(c) L mol⁻¹ s⁻¹
(d) mol² L⁻² s⁻¹
Answer: (b)
Q7. According to Arrhenius equation, reaction rate increases with
(a) Decrease in temperature
(b) Increase in activation energy
(c) Increase in temperature
(d) Decrease in concentration
Answer: (c)
Q8. Kohlrausch’s law is used to calculate
(a) pH
(b) Limiting molar conductivity
(c) Cell constant
(d) Transport number
Answer: (b)
Section B: Inorganic Chemistry (Board Practice MCQs)
Q9. Variable oxidation states of transition metals are due to
(a) Large atomic size
(b) Partially filled d-orbitals
(c) High density
(d) Metallic bonding
Answer: (b)
Q10. Colour of transition metal ions is due to
(a) Charge transfer
(b) d–d transitions
(c) f–f transitions
(d) Metallic bonding
Answer: (b)
Q11. Lanthanoid contraction occurs because of
(a) High atomic mass
(b) Poor shielding by 4f electrons
(c) Metallic bonding
(d) High density
Answer: (b)
Q12. Coordination number of Fe in [Fe(CN)₆]³⁻ is
(a) 3
(b) 4
(c) 5
(d) 6
Answer: (d)
Q13. Oxalate ion acts as a
(a) Monodentate ligand
(b) Ambidentate ligand
(c) Bidentate ligand
(d) Neutral ligand
Answer: (c)
Q14. Geometry of SF₆ molecule is
(a) Tetrahedral
(b) Square planar
(c) Trigonal bipyramidal
(d) Octahedral
Answer: (d)
Q15. Maximum catenation is shown by
(a) Nitrogen
(b) Oxygen
(c) Carbon
(d) Silicon
Answer: (c)
Section C: Organic Chemistry (Reaction-Based Practice MCQs)
Q16. SN1 reactions are favoured by
(a) Primary carbocation
(b) Secondary carbocation
(c) Tertiary carbocation
(d) Methyl carbocation
Answer: (c)
Q17. Lucas test is used to distinguish
(a) Aldehydes and ketones
(b) Phenols and ethers
(c) Primary, secondary and tertiary alcohols
(d) Amines
Answer: (c)
Q18. Phenol is more acidic than ethanol due to
(a) Inductive effect
(b) Resonance stabilisation
(c) Hydrogen bonding
(d) Molecular mass
Answer: (b)
Q19. Tollens’ reagent gives silver mirror with
(a) Ketones
(b) Aldehydes
(c) Alcohols
(d) Acids
Answer: (b)
Q20. Cannizzaro reaction occurs in aldehydes
(a) With α-hydrogen
(b) Without α-hydrogen
(c) Aromatic only
(d) Aliphatic only
Answer: (b)
Q21. Aniline is less basic than methylamine due to
(a) +I effect
(b) –I effect
(c) Resonance
(d) Steric hindrance
Answer: (c)
Q22. Diazonium salts are prepared below 5 °C because they
(a) React slowly
(b) Are unstable at higher temperature
(c) Need excess acid
(d) Are endothermic
Answer: (b)
Section D: Biomolecules, Polymers & Everyday Chemistry
Q23. Glucose is a
(a) Disaccharide
(b) Polysaccharide
(c) Monosaccharide
(d) Glycoprotein
Answer: (c)
Q24. Proteins are polymers of
(a) Fatty acids
(b) Amino acids
(c) Nucleotides
(d) Glucose
Answer: (b)
Q25. Peptide bond is formed between
(a) Two sugars
(b) Two amino acids
(c) Two fatty acids
(d) Two nucleotides
Answer: (b)
Q26. Nylon-6,6 is a
(a) Addition polymer
(b) Condensation polymer
(c) Natural polymer
(d) Elastomer
Answer: (b)
Q27. Buna-S is a copolymer of
(a) Butadiene and styrene
(b) Isoprene and styrene
(c) Ethene and propene
(d) Vinyl chloride and styrene
Answer: (a)
Q28. Analgesics are drugs used to
(a) Reduce fever
(b) Kill bacteria
(c) Relieve pain
(d) Induce sleep
Answer: (c)
Q29. Which is a non-narcotic analgesic?
(a) Morphine
(b) Codeine
(c) Aspirin
(d) Heroin
Answer: (c)
Q30. Antibiotics are ineffective against
(a) Bacteria
(b) Fungi
(c) Viruses
(d) Protozoa
Answer: (c)
Section E: High-Scoring Board Logic MCQs
Q31. Zero-order reaction shows linear plot of
(a) log[A] vs t
(b) 1/[A] vs t
(c) [A] vs t
(d) k vs t
Answer: (c)
Q32. Chelation increases stability of complexes due to
(a) Size effect
(b) Entropy increase
(c) Charge increase
(d) Steric effect
Answer: (b)
Q33. Monomer of Teflon is
(a) Ethene
(b) Styrene
(c) Vinyl chloride
(d) Tetrafluoroethylene
Answer: (d)
Q34. Vitamin C is
(a) Fat-soluble
(b) Water-soluble
(c) Hormone
(d) Enzyme
Answer: (b)
Q35. Insulin is a
(a) Vitamin
(b) Lipid
(c) Hormone
(d) Carbohydrate
Answer: (c)
Q36. Hydrophilic part of soap is
(a) Hydrocarbon chain
(b) –COO⁻ group
(c) Alkyl group
(d) Benzene ring
Answer: (b)
Q37. Strongest acid among hydrogen halides is
(a) HF
(b) HCl
(c) HBr
(d) HI
Answer: (d)
Q38. Most electronegative element is
(a) Oxygen
(b) Nitrogen
(c) Chlorine
(d) Fluorine
Answer: (d)
Q39. Approximate pH of human blood is
(a) 5.6
(b) 6.8
(c) 7.4
(d) 8.5
Answer: (c)
Q40. Diazepam is classified as a
(a) Antibiotic
(b) Analgesic
(c) Tranquilizer
(d) Antipyretic
Answer: (c)
Section E: Rapid Board Recall MCQs (Q41–Q50)
Q41. The correct increasing order of reducing power among Zn, Cu and Ag is
(a) Ag < Cu < Zn
(b) Cu < Zn < Ag
(c) Zn < Cu < Ag
(d) Ag < Zn < Cu
Answer: (c)
Explanation: Reducing power decreases with increase in standard reduction potential (E°). Since E° increases from Zn → Cu → Ag, reducing power decreases in the same order.
Q42. Which of the following shows maximum hydrogen bonding?
(a) NH₃
(b) HF
(c) H₂O
(d) CH₄
Answer: (c)
Explanation: Each water molecule can form up to four hydrogen bonds, resulting in extensive hydrogen bonding.
Q43. The hybridisation of boron in BF₃ is
(a) sp
(b) sp²
(c) sp³
(d) dsp²
Answer: (b)
Explanation: Boron forms three σ bonds and has no lone pair, leading to sp² hybridisation and trigonal planar geometry.
Q44. The shape of XeF₄ molecule is
(a) Tetrahedral
(b) Square planar
(c) Trigonal bipyramidal
(d) Octahedral
Answer: (b)
Explanation: XeF₄ has four bond pairs and two lone pairs placed opposite each other, giving a square planar shape.
Q45. Which of the following detergents is biodegradable?
(a) Branched-chain detergents
(b) Phosphate detergents
(c) Straight-chain detergents
(d) Cationic detergents
Answer: (c)
Explanation: Straight-chain detergents are easily decomposed by microorganisms and are environmentally safe.
Q46. Aldol reaction is shown by aldehydes and ketones that
(a) Are aromatic
(b) Are unsaturated
(c) Contain α-hydrogen
(d) Are acidic
Answer: (c)
Explanation: Presence of α-hydrogen is essential for formation of enolate ion in aldol reaction.
Q47. The best laboratory method for preparing primary amines is
(a) Hoffmann bromamide reaction
(b) Gabriel phthalimide synthesis
(c) Reduction of nitro compounds
(d) Ammonolysis of alkyl halides
Answer: (b)
Explanation: Gabriel synthesis selectively yields primary amines without formation of secondary or tertiary amines.
Q48. Electrical conductance of an electrolyte solution increases with
(a) Increase in pressure
(b) Decrease in temperature
(c) Increase in temperature
(d) Decrease in concentration
Answer: (c)
Explanation: Increase in temperature increases ionic mobility, thus increasing conductance.
Q49. Glucose can be identified by
(a) Fehling’s test only
(b) Tollens’ test only
(c) Benedict’s test only
(d) Both Fehling’s and Tollens’ tests
Answer: (d)
Explanation: Glucose is a reducing sugar and gives positive results with both Fehling’s and Tollens’ reagents.
Q50. CBSE Class 12 Chemistry board examinations mainly focus on
(a) Rote memorisation
(b) Advanced numerical problems
(c) Research-oriented chemistry
(d) NCERT concepts and applications
Answer: (d)
Explanation: CBSE board papers are strictly NCERT-based and emphasise conceptual clarity, trends, reactions, and real-life applications.
✅ Rapid Board Recall Completed
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