Preparing for the CBSE Class 12 Chemistry Half-Yearly Exam 2025? A strong strategy involves regular practice of Multiple Choice Questions (MCQs), which helps sharpen conceptual understanding and application skills. Based on the latest CBSE syllabus, we have curated the Top 50 Most Important MCQs to help students revise effectively and boost confidence before the exam.
CBSE Class 12 Chemistry Exam Pattern 2025-26
| Section | Question Type | No. of Questions | Marks Per Question | Total Marks |
| Section A | Multiple Choice Questions | 16 | 1 | 16 |
| Section B | Short Answer Questions | 5 | 2 | 10 |
| Section C | Short Answer Questions | 7 | 3 | 21 |
| Section D | Case-Based Questions | 2 | 4 | 8 |
| Section E | Long Answer Questions | 3 | 5 | 15 |
Study Tip for Students
- Practice solving MCQs without referring to textbooks to assess your real knowledge.
- After attempting, check the provided answer key for quick evaluation.
Top 50 Important Chemistry MCQs for CBSE Class 12 Half-Yearly Exam 2025
- Diamond is a:
(a) Molecular solid (b) Ionic solid (c) Covalent solid (d) Metallic solid
→ Answer: (c) - Coordination number of Na+ in NaCl crystal is:
(a) 6 (b) 8 (c) 4 (d) 12
→ Answer: (a) - In Schottky defect:
(a) Equal number of cations and anions are missing (b) Only cations are missing (c) Only anions are missing (d) None of these
→ Answer: (a) - A solution obeying Raoult’s law is:
(a) Non-ideal solution (b) Ideal solution (c) Azeotropic mixture (d) Colloidal solution
→ Answer: (b) - Which colligative property determines molar mass of a solute?
(a) Osmotic pressure (b) Vapour pressure (c) Surface tension (d) Viscosity
→ Answer: (a) - Henry’s law is related to:
(a) Solid in liquid (b) Gas in liquid (c) Liquid in liquid (d) Gas in solid
→ Answer: (b) - Standard reduction potential of hydrogen electrode is:
(a) +1 V (b) 0 V (c) –1 V (d) 2.303 V
→ Answer: (b) - Conductivity of solution decreases with:
(a) Increase in concentration (b) Decrease in temperature (c) Increase in temperature (d) Increase in dilution
→ Answer: (d) - In a galvanic cell, current flows:
(a) From anode to cathode externally (b) From cathode to anode externally (c) From salt bridge to cathode (d) None
→ Answer: (a) - Unit of rate constant for first-order reaction:
(a) mol L⁻¹ s⁻¹ (b) L mol⁻¹ s⁻¹ (c) s⁻¹ (d) No unit
→ Answer: (c) - Factor not affecting reaction rate:
(a) Temperature (b) Pressure (c) Catalyst (d) Molecularity
→ Answer: (d) - Slope of log [R] vs. time graph gives:
(a) Activation energy (b) Order of reaction (c) Rate constant (d) Molecularity
→ Answer: (c) - Removing colloidal particles by shaking with electrolyte is called:
(a) Coagulation (b) Peptization (c) Dialysis (d) Electrophoresis
→ Answer: (a) - Tyndall effect is observed in:
(a) True solutions (b) Colloidal solutions (c) Suspensions only (d) Both colloids & suspensions
→ Answer: (b) - Adsorption decreasing with increasing temperature is:
(a) Chemical adsorption (b) Physical adsorption (c) Both (a) and (b) (d) None
→ Answer: (b) - Aluminium ore is:
(a) Bauxite (b) Galena (c) Hematite (d) Magnetite
→ Answer: (a) - Zone refining works on:
(a) Volatility (b) Fractional distillation (c) Fractional crystallization (d) Greater impurity solubility in melt
→ Answer: (d) - Froth flotation concentrates:
(a) Sulphide ores (b) Oxide ores (c) Halide ores (d) None
→ Answer: (a) - Heaviest halogen:
(a) Iodine (b) Bromine (c) Astatine (d) Fluorine
→ Answer: (c) - Laughing gas is:
(a) N₂O (b) NO₂ (c) N₂O₃ (d) NO
→ Answer: (a) - Most electronegative element:
(a) Oxygen (b) Chlorine (c) Fluorine (d) Nitrogen
→ Answer: (c) - Transition element:
(a) Zn (b) Cu (c) Ca (d) Mg
→ Answer: (b) - Potassium dichromate is:
(a) Oxidising agent (b) Reducing agent (c) Both (a) and (b) (d) Neutral
→ Answer: (a) - Ion giving blue color in solution:
(a) Fe²⁺ (b) Cu²⁺ (c) Mn²⁺ (d) Zn²⁺
→ Answer: (b) - Coordination number of Co in [Co(NH₃)₆]³⁺:
(a) 4 (b) 6 (c) 3 (d) 8
→ Answer: (b) - Ligand in [Ni(CO)₄]:
(a) CO (b) Ni (c) Both (d) None
→ Answer: (a) - Ambidentate ligand:
(a) CN⁻ (b) NH₃ (c) H₂O (d) CO
→ Answer: (a) - Strongest C–X bond:
(a) C–F (b) C–Cl (c) C–Br (d) C–I
→ Answer: (a) - Mechanism of tertiary haloalkanes:
(a) SN1 (b) SN2 (c) E1 (d) E2
→ Answer: (a) - Refrigerant used:
(a) CFCs (b) Alcohol (c) Ether (d) CO₂
→ Answer: (a) - IUPAC name of CH₃CH₂OH:
(a) Methanol (b) Propanol (c) Ethanol (d) Butanol
→ Answer: (c) - Phenol + FeCl₃ produces:
(a) Blue-violet colour (b) White precipitate (c) Brown ring (d) Yellow colour
→ Answer: (a) - Williamson synthesis prepares:
(a) Alcohols (b) Ethers (c) Phenols (d) Aldehydes
→ Answer: (b) - Fehling’s test distinguishes:
(a) Aldehydes & ketones (b) Alcohols & phenols (c) Acids & esters (d) Amines & amides
→ Answer: (a) - Aldehydes → Alcohols by:
(a) Reduction (b) Oxidation (c) Substitution (d) Hydrolysis
→ Answer: (a) - –COOH group is:
(a) Carboxylic acid (b) Aldehyde (c) Ketone (d) Ester
→ Answer: (a) - Aniline + bromine water →
(a) 2,4,6-tribromoaniline (b) Monobromoaniline (c) p-Bromoaniline (d) None
→ Answer: (a) - Hinsberg’s test distinguishes:
(a) Primary, secondary, tertiary amines (b) Aldehydes & ketones (c) Alcohols & phenols (d) Acids & esters
→ Answer: (a) - Not an amine:
(a) CH₃NH₂ (b) (CH₃)₂NH (c) C₂H₅OH (d) (CH₃)₃N
→ Answer: (c) - Protein building blocks:
(a) Nucleotides (b) Amino acids (c) Monosaccharides (d) Fatty acids
→ Answer: (b) - Insulin deficiency causes:
(a) Diabetes (b) Tuberculosis (c) Malaria (d) Asthma
→ Answer: (a) - Ascorbic acid is:
(a) Vitamin A (b) Vitamin B (c) Vitamin C (d) Vitamin D
→ Answer: (c) - Nylon-6 is obtained from:
(a) Caprolactam (b) Hexamethylenediamine (c) Adipic acid (d) Ethylene glycol
→ Answer: (a) - Natural polymer:
(a) Nylon (b) Bakelite (c) Rubber (d) PVC
→ Answer: (c) - Monomer of polystyrene:
(a) Styrene (b) Ethylene (c) Propylene (d) Vinyl chloride
→ Answer: (a) - Tranquilizer drug:
(a) Valium (b) Ranitidine (c) Omeprazole (d) Aspirin
→ Answer: (a) - Aspirin is:
(a) Analgesic (b) Antipyretic (c) Anti-inflammatory (d) All of these
→ Answer: (d) - Detergents are sodium salts of:
(a) Fatty acids (b) Alkyl benzene sulphonic acids (c) Carboxylic acids (d) Amines
→ Answer: (b) - Antihistamine drug:
(a) Chlorpheniramine (b) Penicillin (c) Aspirin (d) Ofloxacin
→ Answer: (a) - Saccharin sweetness compared to sucrose:
(a) 300x (b) 500x (c) Equal (d) 100x
→ Answer: (a)
