These essential MCQ questions are selected from the most important topics in CBSE Class 12 Chemistry Board Examination 2026. Sections include Solid State, Solutions, Electrochemistry, Chemical Kinetics, Surface Chemistry and Organic Chemistry as per NCERT syllabus. For truely unlimited daily MCQ practice, visit Vooo AI Education.
⚗️ CBSE Class 12 Chemistry
1NaCl crystal has which type of crystal structure?
Answer: B — Face-centred cubic
NaCl (rock salt) has a face-centred cubic (FCC) structure where Na⁺ and Cl⁻ ions alternate. Each Na⁺ is surrounded by 6 Cl⁻ ions and each Cl⁻ is surrounded by 6 Na⁺ ions. The coordination number is 6:6.
NaCl (rock salt) has a face-centred cubic (FCC) structure where Na⁺ and Cl⁻ ions alternate. Each Na⁺ is surrounded by 6 Cl⁻ ions and each Cl⁻ is surrounded by 6 Na⁺ ions. The coordination number is 6:6.
2Which colligative property is used to find molar mass?
Answer: D — All of these
All four colligative properties — relative lowering of vapour pressure, elevation of boiling point, depression of freezing point, and osmotic pressure — can be used to determine the molar mass of solutes. Osmotic pressure is most commonly used for polymers.
All four colligative properties — relative lowering of vapour pressure, elevation of boiling point, depression of freezing point, and osmotic pressure — can be used to determine the molar mass of solutes. Osmotic pressure is most commonly used for polymers.
3The SI unit of electrochemical cell EMF is:
Answer: C — Volt
EMF (Electromotive Force) of an electrochemical cell is measured in Volts (V). It represents the potential difference between the two electrodes. Standard electrode potentials are measured relative to the Standard Hydrogen Electrode (SHE) at 0 V.
EMF (Electromotive Force) of an electrochemical cell is measured in Volts (V). It represents the potential difference between the two electrodes. Standard electrode potentials are measured relative to the Standard Hydrogen Electrode (SHE) at 0 V.
4Which order reaction has constant half-life?
Answer: B — First order
First order reactions have a constant half-life (t₁/₂ = 0.693/k) independent of initial concentration. Zero order half-life depends on initial concentration. Radioactive decay is a classic example of a first order reaction.
First order reactions have a constant half-life (t₁/₂ = 0.693/k) independent of initial concentration. Zero order half-life depends on initial concentration. Radioactive decay is a classic example of a first order reaction.
5The process of adsorption is:
Answer: B — Exothermic
Adsorption is always exothermic because when molecules are adsorbed onto a surface, they lose kinetic energy, which is released as heat. The decrease in surface energy of the adsorbent makes the process thermodynamically spontaneous (ΔG < 0).
Adsorption is always exothermic because when molecules are adsorbed onto a surface, they lose kinetic energy, which is released as heat. The decrease in surface energy of the adsorbent makes the process thermodynamically spontaneous (ΔG < 0).
6Benzene undergoes which type of reaction preferably?
Answer: B — Substitution
Benzene preferably undergoes electrophilic substitution reactions (like nitration, halogenation, sulphonation) rather than addition reactions. This preserves its aromatic stability (delocalised π electrons). Addition would disrupt aromaticity.
Benzene preferably undergoes electrophilic substitution reactions (like nitration, halogenation, sulphonation) rather than addition reactions. This preserves its aromatic stability (delocalised π electrons). Addition would disrupt aromaticity.
7Which functional group is present in alcohols?
Answer: C — –OH
Alcohols contain the hydroxyl functional group (–OH). Aldehydes contain –CHO, carboxylic acids contain –COOH, and ketones contain the carbonyl group (–CO–) between two carbon atoms. Functional groups determine the chemical properties of organic compounds.
Alcohols contain the hydroxyl functional group (–OH). Aldehydes contain –CHO, carboxylic acids contain –COOH, and ketones contain the carbonyl group (–CO–) between two carbon atoms. Functional groups determine the chemical properties of organic compounds.
8Hybridisation of carbon in methane (CH₄) is:
Answer: C — sp³
Carbon in methane has sp³ hybridisation. One 2s and three 2p orbitals mix to form four equivalent sp³ hybrid orbitals arranged tetrahedrally at 109.5°. This gives methane its tetrahedral shape with four identical C–H bonds.
Carbon in methane has sp³ hybridisation. One 2s and three 2p orbitals mix to form four equivalent sp³ hybrid orbitals arranged tetrahedrally at 109.5°. This gives methane its tetrahedral shape with four identical C–H bonds.
9Which catalyst is used in Haber's process?
Answer: B — Iron
Iron (with molybdenum as a promoter) is the catalyst in the Haber process for synthesis of ammonia: N₂ + 3H₂ ⇌ 2NH₃. Conditions: 450–500°C, 200 atm pressure. V₂O₅ is used in the Contact process for H₂SO₄ production.
Iron (with molybdenum as a promoter) is the catalyst in the Haber process for synthesis of ammonia: N₂ + 3H₂ ⇌ 2NH₃. Conditions: 450–500°C, 200 atm pressure. V₂O₅ is used in the Contact process for H₂SO₄ production.
10The IUPAC name of CH₃–CH₂–OH is:
Answer: B — Ethanol
CH₃–CH₂–OH is ethanol (2 carbon atoms + hydroxyl group). IUPAC naming: count carbons (ethane = 2C), add suffix -ol for alcohol = ethanol. Methanol is CH₃OH (1C), propanol is C₃H₇OH (3C), butanol is C₄H₉OH (4C).
CH₃–CH₂–OH is ethanol (2 carbon atoms + hydroxyl group). IUPAC naming: count carbons (ethane = 2C), add suffix -ol for alcohol = ethanol. Methanol is CH₃OH (1C), propanol is C₃H₇OH (3C), butanol is C₄H₉OH (4C).
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