CBSE 12th Half-Yearly Exam 2025-26 : Chemistry Top 50 MCQs with Answers

Q5. Which colligative property is used to determine the molar mass of a solute?

(a) Osmotic pressure
(b) Vapour pressure
(c) Surface tension
(d) Viscosity

Answer. a

👉 Read Also -  CBSE Class 12 Maths Half Yearly Sample Paper 2025 with Solutions PDF

Q6. Henry’s law is related to:

(a) Solid in liquid
(b) Gas in liquid
(c) Liquid in liquid
(d) Gas in solid

Answer. b

Q7. The standard reduction potential of hydrogen electrode is:

(a) +1 V
(b) 0 V
(c) –1 V
(d) 2.303 V

Answer. b

Q8. Conductivity of a solution decreases with:

(a) Increase in concentration
(b) Decrease in temperature
(c) Increase in temperature
(d) Increase in dilution

Answer. d

Q9. In a galvanic cell, the flow of current is:

(a) From anode to cathode externally
(b) From cathode to anode externally
(c) From salt bridge to cathode
(d) None of the above

Answer. a

👉 Read Also - CBSE Class 12 Chemistry Half Yearly Sample Paper 2025 with Solutions PDF

Q10. The unit of rate constant for a first-order reaction is:

(a) mol L⁻¹ s⁻¹
(b) L mol⁻¹ s⁻¹
(c) s⁻¹
(d) No unit

Answer. c

Q11. Which factor does not affect the rate of a reaction?

(a) Temperature
(b) Pressure
(c) Catalyst
(d) Molecularity

Answer. d

Q12. The slope of a straight line obtained by plotting log [R] versus time gives:

(a) Activation energy
(b) Order of reaction
(c) Rate constant
(d) Molecularity

Answer. c

Q13. The process of removing colloidal particles by shaking with electrolyte is called:

(a) Coagulation
(b) Peptization
(c) Dialysis
(d) Electrophoresis

Answer. a

Q14. Tyndall effect is observed in:

(a) True solutions
(b) Colloidal solutions
(c) Suspensions only
(d) Both colloids and suspensions

Answer. b

Q15. Which type of adsorption decreases with increase in temperature?

(a) Chemical adsorption
(b) Physical adsorption
(c) Both (a) and (b)
(d) None

Answer. b

👉 Read Also - CBSE Class 12 Biology Half Yearly Sample Question Paper 2025-26 with Solutions PDF

Q16. Which of the following is an ore of aluminium?

(a) Bauxite
(b) Galena
(c) Hematite
(d) Magnetite

Answer. a

Q17. The method of zone refining is based on the principle of:

(a) Volatility
(b) Fractional distillation
(c) Fractional crystallization
(d) Greater solubility of impurities in the melt

Answer. d

Q18. Froth flotation process is used for the concentration of:

(a) Sulphide ores
(b) Oxide ores
(c) Halide ores
(d) None

Answer. a

Q19. Which is the heaviest halogen?

(a) Iodine
(b) Bromine
(c) Astatine
(d) Fluorine

Answer. c

Q20. Which gas is known as laughing gas?

(a) N₂O
(b) NO₂
(c) N₂O₃
(d) NO

Answer. a

👉 Read Also - CBSE 12th Half-Yearly Exams 2025: Important Topics & Preparation Tips

Q21. Which of the following is the most electronegative element?

(a) Oxygen
(b) Chlorine
(c) Fluorine
(d) Nitrogen

Answer. c

Q22. Which among the following is a transition element?

(a) Zn
(b) Cu
(c) Ca
(d) Mg

Answer. b

Q23. Potassium dichromate is:

(a) Oxidising agent
(b) Reducing agent
(c) Both
(d) Neutral

Answer. a

Q24. Which ion imparts blue colour to aqueous solutions?

(a) Fe²⁺
(b) Cu²⁺
(c) Mn²⁺
(d) Zn²⁺

Answer. b

Q25. The coordination number of Co in [Co(NH₃)₆]³⁺ is:

(a) 4
(b) 6
(c) 3
(d) 8

Answer. b

Q26. The ligand in [Ni(CO)₄] is:

(a) CO
(b) Ni
(c) Both
(d) None

Answer. a

Q27. Which of the following is an ambidentate ligand?

(a) CN⁻
(b) NH₃
(c) H₂O
(d) CO

Answer. a

Q28. The C–X bond strength is highest in:

(a) C–F
(b) C–Cl
(c) C–Br
(d) C–I

Answer. a

Q29. Which reaction mechanism is followed by tertiary haloalkanes?

(a) SN1
(b) SN2
(c) E1
(d) E2

Answer. a

Q30. Which of the following is used as a refrigerant?

(a) CFCs
(b) Alcohol
(c) Ether
(d) CO₂

Answer. a

👉 CBSE Class 12 Study Materials

Q31. The IUPAC name of CH₃CH₂OH is:

(a) Methanol
(b) Propanol
(c) Ethanol
(d) Butanol

Answer. c

Q32. Phenol on reaction with FeCl₃ gives:

(a) Blue-violet colour
(b) White precipitate
(c) Brown ring
(d) Yellow colour

Answer. a

Q33. Williamson synthesis is used for the preparation of:

(a) Alcohols
(b) Ethers
(c) Phenols
(d) Aldehydes

Answer. b

Q34. Fehling’s test is used to distinguish:

(a) Aldehydes and ketones
(b) Alcohols and phenols
(c) Acids and esters
(d) Amines and amides

Answer. a

Q35. Which reaction converts aldehydes into alcohols?

(a) Reduction
(b) Oxidation
(c) Substitution
(d) Hydrolysis

Answer. a

Q36. The functional group –COOH represents:

(a) Carboxylic acid
(b) Aldehyde
(c) Ketone
(d) Ester

Answer. a

👉 Read Also - CBSE 12th Economics Half-Yearly Exam 2025-26: Sample Practice Paper

Q37. Aniline reacts with bromine water to give:

(a) 2,4,6-tribromoaniline
(b) Monobromoaniline
(c) p-Bromoaniline
(d) None

Answer. a

Q38. Hinsberg’s test is used to distinguish:

(a) Primary, secondary, and tertiary amines
(b) Aldehydes and ketones
(c) Alcohols and phenols
(d) Acids and esters

Answer. a

Q39. Which of the following is not an amine?

(a) CH₃NH₂
(b) (CH₃)₂NH
(c) C₂H₅OH
(d) (CH₃)₃N

Answer. c

Q40. The building blocks of proteins are:

(a) Nucleotides
(b) Amino acids
(c) Monosaccharides
(d) Fatty acids

Answer. b

Q41. The deficiency of insulin causes:

(a) Diabetes
(b) Tuberculosis
(c) Malaria
(d) Asthma

Answer. a

Q42. Which vitamin is also known as ascorbic acid?

(a) Vitamin A
(b) Vitamin B
(c) Vitamin C
(d) Vitamin D

Answer. c

Q43. Nylon-6 is obtained from:

(a) Caprolactam
(b) Hexamethylenediamine
(c) Adipic acid
(d) Ethylene glycol

Answer. a

Q44. Which of the following is a natural polymer?

(a) Nylon
(b) Bakelite
(c) Rubber
(d) PVC

Answer. c

Q45. The monomer of polystyrene is:

(a) Styrene
(b) Ethylene
(c) Propylene
(d) Vinyl chloride

Answer. a

Q46. Which drug is used as a tranquilizer?

(a) Valium
(b) Ranitidine
(c) Omeprazole
(d) Aspirin

Answer. a

Q47. Aspirin is used as:

(a) Analgesic
(b) Antipyretic
(c) Anti-inflammatory
(d) All of these

Answer. d

Q48. Detergents are sodium salts of:

(a) Fatty acids
(b) Alkyl benzene sulphonic acids
(c) Carboxylic acids
(d) Amines

Answer. b

Q49. Which of the following is an antihistamine?

(a) Chlorpheniramine
(b) Penicillin
(c) Aspirin
(d) Ofloxacin

Answer. a

Q50. Artificial sweetener saccharin is:

(a) 300 times sweeter than sucrose
(b) 500 times sweeter than sucrose
(c) Equal to sucrose
(d) 100 times sweeter than sucrose

Answer. a