Q.1 Which of the following is NOT a colligative property?
Vapor pressure lowering
Boiling point elevation
Osmotic pressure
Viscosity
Explanation - Colligative properties depend on the number of solute particles, not on their nature. Viscosity is a physical property but not a colligative property.
Correct answer is: Viscosity
Q.2 Raoult’s law is applicable to which type of solutions?
Ideal solutions
Non-ideal solutions
Saturated solutions
Colloidal solutions
Explanation - Raoult's law states that the partial vapor pressure of each component in an ideal solution is directly proportional to its mole fraction.
Correct answer is: Ideal solutions
Q.3 Which of the following increases the solubility of gases in liquids?
Increase in temperature
Decrease in temperature
Decrease in pressure
Adding a non-volatile solute
Explanation - Gas solubility in liquids generally decreases with increase in temperature and increases with decrease in temperature.
Correct answer is: Decrease in temperature
Q.4 The osmotic pressure of a solution depends on
Volume of solution
Concentration of solute
Nature of solvent only
Viscosity of solution
Explanation - Osmotic pressure is directly proportional to the molar concentration of solute particles in the solution.
Correct answer is: Concentration of solute
Q.5 Which of the following solutions will have the highest vapor pressure?
0.1 M NaCl
0.1 M Glucose
0.2 M Glucose
Pure solvent
Explanation - Adding solute lowers the vapor pressure (Raoult’s law). The pure solvent has the highest vapor pressure.
Correct answer is: Pure solvent
Q.6 A solution containing 1 mole of urea in 1 kg of water has freezing point depression of 1.86°C. What is the van’t Hoff factor (i) for urea?
1
2
3
0
Explanation - Urea is a non-electrolyte; it does not dissociate in water, so i = 1.
Correct answer is: 1
Q.7 Which of the following is an example of a hypertonic solution?
0.9% NaCl solution
5% NaCl solution
Pure water
Glucose solution with same osmotic pressure as cells
Explanation - A hypertonic solution has higher solute concentration than the cell, causing water to move out of the cell.
Correct answer is: 5% NaCl solution
Q.8 Molality is defined as
Moles of solute per litre of solution
Moles of solute per kg of solvent
Mass of solute per mass of solvent
Volume of solute per volume of solution
Explanation - Molality (m) = moles of solute / mass of solvent in kg. It is temperature independent.
Correct answer is: Moles of solute per kg of solvent
Q.9 Which of the following is TRUE for ideal solutions?
∆H_mix > 0 and ∆V_mix ≈ 0
∆H_mix = 0 and ∆V_mix ≈ 0
∆H_mix < 0 and ∆V_mix < 0
∆H_mix = 0 and ∆V_mix > 0
Explanation - For ideal solutions, enthalpy of mixing is zero and volume change is negligible.
Correct answer is: ∆H_mix = 0 and ∆V_mix ≈ 0
Q.10 The van’t Hoff factor (i) for Na2SO4 in aqueous solution is
1
2
3
4
Explanation - Na2SO4 dissociates as Na2SO4 → 2Na+ + SO4^2-, producing 3 ions, so i = 3.
Correct answer is: 3
Q.11 Boiling point elevation is directly proportional to
Mass of solute
Mole fraction of solvent
Molality of solute
Density of solution
Explanation - ΔT_b = K_b × m × i, where m is molality and i is van’t Hoff factor.
Correct answer is: Molality of solute
Q.12 Henry’s law states that
Solubility of gas ∝ pressure of gas
Solubility of gas ∝ √pressure
Solubility of gas ∝ 1/pressure
Solubility of gas is independent of pressure
Explanation - Henry’s law: C = kP, where C is solubility and P is partial pressure of the gas.
Correct answer is: Solubility of gas ∝ pressure of gas
Q.13 Colligative properties depend on
Nature of solute
Nature of solvent
Number of solute particles
Type of container
Explanation - Colligative properties are independent of chemical nature and depend only on the quantity of solute particles.
Correct answer is: Number of solute particles
Q.14 Which of the following solutions is hypotonic to red blood cells?
0.9% NaCl solution
5% NaCl solution
Pure water
Glucose solution iso-osmotic to cells
Explanation - A hypotonic solution has lower solute concentration than cells, causing them to swell.
Correct answer is: Pure water
Q.15 The molar mass of a non-volatile solute can be determined by
Freezing point depression
Boiling point elevation
Osmotic pressure
All of the above
Explanation - Colligative properties like freezing point depression, boiling point elevation, and osmotic pressure can be used to determine molar mass.
Correct answer is: All of the above
Q.16 Vapor pressure of a solution decreases when
Solute is volatile
Solute is non-volatile
Solvent is volatile
Solvent is non-volatile
Explanation - Addition of a non-volatile solute lowers the vapor pressure of the solvent (Raoult’s law).
Correct answer is: Solute is non-volatile
Q.17 Which of the following is an example of an ideal solution?
Benzene and toluene
Water and ethanol
Acetic acid and water
Hydrochloric acid and water
Explanation - Ideal solutions have similar intermolecular forces, e.g., benzene and toluene mix without heat or volume change.
Correct answer is: Benzene and toluene
Q.18 The depression in freezing point for 1 molal solution of a non-electrolyte in water is
1.86°C
0.512°C
3.72°C
0.1°C
Explanation - ΔT_f = K_f × m. For water, K_f = 1.86 K kg mol^-1, and m = 1 molal.
Correct answer is: 1.86°C
Q.19 Which of the following affects the rate of osmosis?
Temperature
Concentration gradient
Membrane area and thickness
All of the above
Explanation - Osmotic rate depends on temperature, solute concentration gradient, and properties of the semipermeable membrane.
Correct answer is: All of the above
Q.20 Boiling point elevation occurs because
Vapor pressure of solution is higher than solvent
Vapor pressure of solution is lower than solvent
Solute reacts with solvent
Solvent evaporates faster
Explanation - Lower vapor pressure requires higher temperature to boil, causing boiling point elevation.
Correct answer is: Vapor pressure of solution is lower than solvent
Q.21 Which law relates vapor pressure of solvent in solution to mole fraction?
Raoult's law
Henry’s law
Dalton’s law
Graham’s law
Explanation - Raoult's law: P_solvent = X_solvent × P°_solvent, where X_solvent is mole fraction.
Correct answer is: Raoult's law
Q.22 The osmotic pressure of 0.1 M NaCl solution at 25°C is approximately:
4.92 atm
2.46 atm
0.5 atm
1 atm
Explanation - Osmotic pressure π = iMRT. For NaCl, i ≈ 2, M = 0.1 mol/L, R = 0.0821 L·atm/mol·K, T = 298K, π ≈ 4.92 atm.
Correct answer is: 4.92 atm
Q.23 In an ideal solution, the forces between unlike molecules are
Stronger than like molecules
Weaker than like molecules
Equal to like molecules
Zero
Explanation - Ideal solutions have intermolecular forces between unlike molecules equal to those between like molecules.
Correct answer is: Equal to like molecules
Q.24 Which of the following colligative properties is measured using a semipermeable membrane?
Boiling point elevation
Freezing point depression
Osmotic pressure
Vapor pressure lowering
Explanation - Osmotic pressure requires a semipermeable membrane to separate solvent from solute.
Correct answer is: Osmotic pressure