NCERT BOOK CLASS 12TH CHEMISTRY MCQ
Chapter 1 : Solutions
Important MCQs with Answers
1. What is the definition of a Solution?
a) A homogeneous mixture
b) A heterogeneous mixture
c) Only a liquid mixture
d) Only a solid mixture
Answer: a) A homogeneous mixture
2. What is the difference between a Solute and a Solvent?
a) The solute is present in greater quantity
b) The solvent is present in lesser quantity
c) The solvent is present in greater quantity
d) Both are present in equal quantities
Answer: c) The solvent is present in greater quantity
3. What is the unit of Molality?
a) mol/L
b) mol/kg
c) g/L
d) % w/w
Answer: b) mol/kg
4. On what does Molarity depend?
a) Temperature
b) Pressure
c) Volume
d) Mass
Answer: a) Temperature
5. What is Henry’s Law related to?
a) Solubility of gases
b) Vapor pressure of liquids
c) Melting point of solids
d) Electrolytes
Answer: a) Solubility of gases
6. For which type of solution is Raoult’s Law valid?
a) Ideal solution
b) Non-ideal solution
c) Only gaseous solutions
d) Only solid solutions
Answer: a) Ideal solution
7. A solution in which the intermolecular forces between solute and solvent are similar is called:
a) Non-ideal solution
b) Ideal solution
c) Saturated solution
d) Unsaturated solution
Answer: b) Ideal solution
8. Boiling point elevation occurs due to:
a) Presence of solute
b) Presence of solvent
c) Decrease in temperature
d) Increase in pressure
Answer: a) Presence of solute
9. Osmotic pressure is given by which formula?
a) PV = nRT
b) P = n/V RT
c) π = CRT
d) P = hρg
Answer: c) π = CRT
10. What does the Van’t Hoff factor indicate?
a) Concentration of the solution
b) Degree of ionization of the solute
c) Pressure of the solvent
d) Volume of the solution
Answer: b) Degree of ionization of the solute
11. A 1 molal solution means:
a) 1 mole of solute in 1 liter of solvent
b) 1 mole of solute in 1 kilogram of solvent
c) 1 gram of solute in 100 mL of solvent
d) 1 mole of solute in 1000 mL of solution
Answer: b) 1 mole of solute in 1 kilogram of solvent
12. For which solution does Raoult’s Law apply completely?
a) Benzene + Toluene
b) Ethanol + Water
c) HCl + Water
d) NaCl + Water
Answer: a) Benzene + Toluene
13. Solutions with dissimilar intermolecular forces are called:
a) Ideal solutions
b) Non-ideal solutions
c) Dilute solutions
d) Concentrated solutions
Answer: b) Non-ideal solutions
14. Which gas has the highest solubility in water?
a) N₂
b) O₂
c) CO₂
d) H₂
Answer: c) CO₂
15. The vapor pressure of a solution is lower than that of the pure solvent. This is related to which law?
a) Henry’s Law
b) Raoult’s Law
c) Dalton’s Law
d) Le Chatelier’s Principle
Answer: b) Raoult’s Law
16. Which method can be used to determine molecular weight?
a) Osmotic pressure
b) Evaporation
c) Distillation
d) Crystallization
Answer: a) Osmotic pressure
17. Freezing point depression is proportional to:
a) Molality of the solution
b) Molarity of the solution
c) Pressure of the solution
d) Temperature of the solution
Answer: a) Molality of the solution
18. What is the Van’t Hoff factor (i) for a 0.1 M NaCl solution?
a) 1
b) 1.5
c) 2
d) 0.5
Answer: c) 2 (Because NaCl → Na⁺ + Cl⁻)
19. The vapor pressure of a solution increases if:
a) The solute is non-volatile
b) The solute is volatile
c) The amount of solvent decreases
d) Temperature decreases
Answer: b) The solute is volatile
20. In which solution is positive deviation observed?
a) Acetone + Carbon disulfide
b) Benzene + Toluene
c) HCl + Water
d) NaOH + Water
Answer: a) Acetone + Carbon disulfide
21. In which solution is negative deviation observed?
a) Ethanol + Water
b) Chloroform + Acetone
c) Benzene + Toluene
d) Hexane + Heptane
Answer: b) Chloroform + Acetone
22. At what temperature is osmotic pressure measured?
a) 0°C
b) 25°C
c) 100°C
d) 273 K
Answer: b) 25°C
23. A 5% (w/w) glucose solution means:
a) 5 grams of glucose in 100 grams of solution
b) 5 grams of glucose in 100 mL of solution
c) 5 moles of glucose in 1 liter of solution
d) 5 grams of glucose in 1 kilogram of solvent
Answer: a) 5 grams of glucose in 100 grams of solution
24. In which solution is the mole fraction unitless?
a) Molality
b) Molarity
c) Mass percentage
d) Mole fraction itself is unitless
Answer: d) Mole fraction itself is unitless
25. In which solution are the solute particles larger?
a) True solution
b) Colloidal solution
c) Suspension
d) Concentrated solution
Answer: b) Colloidal solution
26. What is the value of ∆mixH (Enthalpy of mixing) for an ideal solution?
a) Zero
b) Positive
c) Negative
d) Infinite
Answer: a) Zero
27. Which solution will have the highest osmotic pressure?
a) 0.1 M Glucose
b) 0.1 M NaCl
c) 0.1 M CaCl₂
d) 0.1 M Urea
Answer: c) 0.1 M CaCl₂ (i = 3)
28. Which solution will show the greatest freezing point depression?
a) 1 M Glucose
b) 1 M NaCl
c) 1 M K₂SO₄
d) 1 M CH₃COOH
Answer: c) 1 M K₂SO₄ (i = 3)
29. Which solution will have the least boiling point elevation?
a) 0.1 M NaCl
b) 0.1 M BaCl₂
c) 0.1 M FeCl₃
d) 0.1 M Glucose
Answer: d) 0.1 M Glucose (i = 1)
30. In which solution does solubility decrease with an increase in temperature?
a) NH₄Cl
b) KNO₃
c) NaCl
d) Ca(OH)₂
Answer: d) Ca(OH)₂
31. In which type of solution does solubility increase with an increase in pressure?
a) Solid-liquid solution
b) Liquid-liquid solution
c) Gas-liquid solution
d) Solid-solid solution
Answer: c) Gas-liquid solution
32. The osmotic pressure of 0.1 M NaCl solution will be how many times that of 0.1 M glucose solution?
a) 1 time
b) 2 times
c) 0.5 times
d) Equal
Answer: b) 2 times (NaCl → Na⁺ + Cl⁻, i = 2)
33. Which solution will have the highest Van’t Hoff factor?
a) 0.1 M Urea
b) 0.1 M NaCl
c) 0.1 M K₂SO₄
d) 0.1 M CH₃COOH
Answer: c) 0.1 M K₂SO₄ (K₂SO₄ → 2K⁺ + SO₄²⁻, i = 3)
34. If a solution’s vapor pressure is higher than predicted by Raoult’s Law, what type of solution is it?
a) Ideal solution
b) Solution showing positive deviation
c) Solution showing negative deviation
d) Saturated solution
Answer: b) Solution showing positive deviation
35. In which solution does solubility increase with temperature?
a) Ca(OH)₂
b) CO₂ (gas)
c) NaCl
d) KNO₃
Answer: d) KNO₃
36. What is the formula for calculating the mole fraction of a solute in a solution?
a) n₁ / (n₁ + n₂)
b) n₂ / (n₁ + n₂)
c) n₁ / n₂
d) n₂ / n₁
Answer: a) n₁ / (n₁ + n₂)
37. How many moles of solute are present in a 1 molal (1 m) solution?
a) 1 mole of solute per 1 liter of solvent
b) 1 mole of solute per 1 kilogram of solvent
c) 1 mole of solute per 1000 mL of solution
d) 1 gram of solute per 100 mL of solvent
Answer: b) 1 mole of solute per 1 kilogram of solvent
38. Which solution does not show freezing point depression?
a) 0.1 M NaCl
b) 0.1 M Glucose
c) 0.1 M CH₃COOH
d) Pure water
Answer: d) Pure water
39. Which solution will have the lowest osmotic pressure?
a) 0.1 M NaCl
b) 0.1 M CaCl₂
c) 0.1 M Glucose
d) 0.1 M AlCl₃
Answer: c) 0.1 M Glucose (i = 1)
40. Which solution will show the highest boiling point elevation?
a) 0.1 M NaCl
b) 0.1 M K₂SO₄
c) 0.1 M Glucose
d) 0.1 M CH₃COOH
Answer: b) 0.1 M K₂SO₄ (i = 3)
41. If the Van’t Hoff factor (i) for an electrolyte is 2.5, what does it indicate?
a) Partial ionization of the solute
b) Complete ionization of the solute
c) Association of the solute
d) Dissociation of the solute
Answer: d) Dissociation of the solute
42. A solution contains 10% (w/w) glucose. What is the mass percentage of the solvent?
a) 10%
b) 90%
c) 100%
d) 50%
Answer: b) 90%
43. In which solution does solubility decrease with temperature?
a) KNO₃
b) NaCl
c) Ca(OH)₂
d) NH₄Cl
Answer: c) Ca(OH)₂
44. What is the ratio of osmotic pressures of 0.1 M NaCl and 0.1 M glucose solutions?
a) 1:1
b) 1:2
c) 2:1
d) 1:3
Answer: c) 2:1
45. For which solution does Raoult’s Law not apply perfectly?
a) Benzene + Toluene
b) Hexane + Heptane
c) Ethanol + Water
d) Chloroform + Acetone
Answer: c) Ethanol + Water
46. Which solution shows negative deviation?
a) Acetone + Carbon disulfide
b) Benzene + Toluene
c) Chloroform + Acetone
d) Hexane + Heptane
Answer: c) Chloroform + Acetone
47. In which solution is solubility independent of pressure?
a) Gas-liquid solution
b) Solid-liquid solution
c) Liquid-liquid solution
d) Gas-solid solution
Answer: b) Solid-liquid solution
48. In which solution are the solute particles the smallest?
a) True solution
b) Colloidal solution
c) Suspension
d) Emulsion
Answer: a) True solution
49. If a solution’s vapor pressure is lower than predicted by Raoult’s Law, what type of solution is it?
a) Ideal solution
b) Solution showing positive deviation
c) Solution showing negative deviation
d) Saturated solution
Answer: c) Solution showing negative deviation
50. Which solution will have the highest osmotic pressure?
a) 0.1 M NaCl
b) 0.1 M CaCl₂
c) 0.1 M AlCl₃
d) 0.1 M Glucose
Answer: c) 0.1 M AlCl₃ (AlCl₃ → Al³⁺ + 3Cl⁻, i = 4)
51. What will be the mass of glucose in a 0.5 molal glucose solution containing 1 kg of water? (Molecular mass of glucose = 180 g/mol)
a) 180 g
b) 90 g
c) 360 g
d) 45 g
Answer: b) 90 g
Explanation:
Molality = Moles of solute / kg of solvent
⇒ 0.5 = n / 1 ⇒ n = 0.5 moles
Mass = Moles × Molecular mass = 0.5 × 180 = 90 g
52. What will be the mass of NaCl in 250 mL of 0.1 M NaCl solution? (Molecular mass of NaCl = 58.5 g/mol)
a) 1.4625 g
b) 2.925 g
c) 5.85 g
d) 0.585 g
Answer: a) 1.4625 g
Explanation:
Molarity = Moles / Volume (L)
⇒ 0.1 = n / 0.25 ⇒ n = 0.025 moles
Mass = 0.025 × 58.5 = 1.4625 g
53. What does a 5% (w/v) glucose solution mean?
a) 5 g glucose in 100 mL solution
b) 5 g glucose in 100 g solution
c) 5 g glucose in 1 L solution
d) 5 moles glucose in 100 mL solution
Answer: a) 5 g glucose in 100 mL solution
54. What will be the molarity of a solution prepared by dissolving 18 g of glucose (C₆H₁₂O₆) in 2 L of water? (Molecular mass of glucose = 180 g/mol)
a) 0.05 M
b) 0.1 M
c) 0.2 M
d) 0.5 M
Answer: a) 0.05 M
Explanation:
Moles = 18 / 180 = 0.1 moles
Molarity = 0.1 / 2 = 0.05 M
55. If the osmotic pressure of 0.1 M NaCl solution is 4.92 atm, what will be the osmotic pressure of 0.1 M glucose solution?
a) 2.46 atm
b) 4.92 atm
c) 9.84 atm
d) 1.23 atm
Answer: a) 2.46 atm
Explanation:
For NaCl (i = 2): π = iCRT ⇒ 4.92 = 2 × (0.1)RT
For glucose (i = 1): π = 1 × (0.1)RT = 4.92 / 2 = 2.46 atm
56. What will be the boiling point elevation of a solution prepared by dissolving 34.2 g of sucrose (C₁₂H₂₂O₁₁) in 1 kg of water? (Kb = 0.52 K kg/mol, Molecular mass of sucrose = 342 g/mol)
a) 0.052 K
b) 0.52 K
c) 0.104 K
d) 1.04 K
Answer: a) 0.052 K
Explanation:
Moles = 34.2 / 342 = 0.1 moles
Molality = 0.1 / 1 = 0.1 m
ΔTb = Kb × m = 0.52 × 0.1 = 0.052 K
57. What will be the freezing point depression of a solution prepared by dissolving 3.0 g of urea (NH₂CONH₂) in 1000 g of water? (Kf = 1.86 K kg/mol, Molecular mass of urea = 60 g/mol)
a) 0.093 K
b) 0.186 K
c) 0.372 K
d) 1.86 K
Answer: a) 0.093 K
Explanation:
Moles = 3 / 60 = 0.05 moles
Molality = 0.05 / 1 = 0.05 m
ΔTf = Kf × m = 1.86 × 0.05 = 0.093 K
58. The Van’t Hoff factor (i) for 0.1 M CH₃COOH (acetic acid) solution is 1.1. What is the percentage ionization of the acid?
a) 1%
b) 5%
c) 10%
d) 20%
Answer: c) 10%
Explanation:
i = 1 + (n – 1)α ⇒ 1.1 = 1 + (2 – 1)α ⇒ α = 0.1 or 10%
59. What will be the mass of HCl in 500 mL of 0.2 M HCl solution? (Molecular mass of HCl = 36.5 g/mol)
a) 3.65 g
b) 7.3 g
c) 14.6 g
d) 36.5 g
Answer: a) 3.65 g
Explanation:
Moles = 0.2 × 0.5 = 0.1 moles
Mass = 0.1 × 36.5 = 3.65 g
60. What will be the new molarity when 200 mL of 0.5 M NaOH solution is mixed with 800 mL of water?
a) 0.1 M
b) 0.2 M
c) 0.4 M
d) 0.5 M
Answer: a) 0.1 M
Explanation:
Moles = 0.5 × 0.2 = 0.1 moles
Total volume = 200 + 800 = 1000 mL = 1 L
New molarity = 0.1 / 1 = 0.1 M
61. In which solution does solubility decrease with an increase in temperature?
a) KNO₃
b) NaCl
c) Ca(OH)₂
d) NH₄Cl
Answer: c) Ca(OH)₂
62. What is the ratio of osmotic pressures of 0.1 M NaCl and 0.1 M CaCl₂ solutions?
a) 1:1
b) 1:2
c) 1:3
d) 2:3
Answer: d) 2:3
Explanation:
For NaCl (i = 2): π₁ = 2 × 0.1 RT
For CaCl₂ (i = 3): π₂ = 3 × 0.1 RT
Ratio = 2:3
63. What will be the osmotic pressure when 1 L of 0.1 M glucose solution is mixed with 1 L of 0.1 M NaCl solution?
a) 0.1 RT
b) 0.2 RT
c) 0.3 RT
d) 0.4 RT
Answer: c) 0.3 RT
Explanation:
For glucose (i = 1): π₁ = 0.1 RT
For NaCl (i = 2): π₂ = 0.2 RT
Total π = 0.1 + 0.2 = 0.3 RT
64. The Van’t Hoff factor (i) for 0.1 M CH₃COOH (acetic acid) solution is 1.1. What percentage of molecules are ionized?
a) 1%
b) 5%
c) 10%
d) 20%
Answer: c) 10%
65. What will be the molality of a solution prepared by dissolving 10 g of urea (NH₂CONH₂) in 100 g of water? (Molecular mass of urea = 60 g/mol)
a) 0.1 m
b) 0.5 m
c) 1.0 m
d) 1.67 m
Answer: d) 1.67 m
Explanation:
Moles = 10 / 60 ≈ 0.1667
Molality = 0.1667 / 0.1 kg = 1.67 m