DPP for NEET: Daily Practice Problems, Ch: Solutions | Chemistry Class 12 PDF Download

Q1: The solubility of a solid in a liquid is significantly affected by temperature changes.
Solute + Solvent ⇌ Solution.
The system being in a dynamic equilibrium must follow Le-Chatelier's principle. Considering Le-Chatelier's principle, which of the following is correct?
(a) ΔH_sol  > 0; solubility ↑; temperature ↓
(b) ΔH_sol  < 0; solubility ↓; temperature ↑
(c) ΔH_sol  > 0; solubility ↓; temperature ↑
(d) ΔH_sol  < 0; solubility ↑; temperature ↑

Q2: The vapour pressure of a solution of the liquids A (P°A = 80 mm Hg and x_A = 0.4) and B (P°B = 120 mm Hg and x_B = 0.6) is found to be 100 mm Hg. It shows that the solution exhibits:
(a) Positive deviation from ideal behaviour
(b) Negative deviation from ideal behaviour
(c) Ideal behaviour
(d) Positive deviation for lower concentration and negative for higher concentration

Q3: Henry's law constant of oxygen is 1.4 × 10^-3 mol·L^-1·atm^-1 at 298 K. How much oxygen is dissolved in 100 mL at 298 K when the partial pressure of oxygen is 0.5 atm?
(a) 1.4 g
(b) 32 g
(c) 22.4 mg
(d) 2.24 mg

Q4: A solution containing components A and B follows Raoult's law when:
(a) A-B attraction force is greater than A-A and B-B
(b) A-B attraction force is less than A-A and B-B
(c) A-B attraction force remains the same as A-A and B-B
(d) Volume of solution is different from the sum of the volume of solute and solvent

Q5: Two 1-litre flasks A and B are connected to each other by a valve, which is closed. Flask A has benzene in equilibrium with its vapours at 30°C. Flask B is evacuated, and the valve is opened. Which of the following is true if the temperature is kept constant?
(a) Some of the benzene molecules would move to flask B from flask A.
(b) Vapour pressure will be half the initial value.
(c) The vapour pressure remains unchanged.
(d) Some more of the liquid benzene in flask A would evaporate.

Q6: For a solution of two liquids A and B, it was proved that P_S = x_A (P°_A − P°_B) + P°_B. The resulting solution will be:
(a) Non-ideal
(b) Ideal
(c) Semi-ideal
(d) None of these

Q7: All form ideal solutions except:
(a) C₆H₆ and C₆H₅CH₃
(b) C₂H₅I and C₂H₅Br
(c) C₆H₅Cl and C₆H₅Br
(d) C₂H₅I and C₂H₅OH

Q8: A binary liquid solution is prepared by mixing n-heptane and ethanol. Which one of the following statements is correct regarding the behaviour of the solution?
(a) The solution is non-ideal, showing - deviation from Raoult's law.
(b) The solution is non-ideal, showing + deviation from Raoult's law.
(c) n-heptane shows + deviation while ethanol shows - deviation from Raoult's law.
(d) The solution formed is an ideal solution.

Q9: During depression of freezing point in a solution, the following are in equilibrium:
(a) Liquid solvent, solid solvent
(b) Liquid solvent, solid solute
(c) Liquid solute, solid solute
(d) Liquid solute, solid solvent

Q10:  Which of the following modes of expressing concentration is independent of temperature?
(a) Molarity
(b) Molality
(c) Formality
(d) Normality

Q11: How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO₃? The concentrated acid is 70% HNO₃.
(a) 90.0 g conc. HNO₃
(b) 70.0 g conc. HNO₃
(c) 54.0 g conc. HNO₃
(d) 45.0 g conc. HNO₃

Q12: Which among the following will show maximum osmotic pressure?
(a) 1 M NaCl
(b) 1 M MgCl₂
(c) 1 M (NH₄)₃PO₄
(d) 1 M Na₂SO₄

Q13: The boiling point of 0.2 mol·kg⁻¹ solution of X in water is greater than the equimolal solution of Y in water. Which one of the following statements is true in this case?
(a) Molecular mass of X is greater than the molecular mass of Y.
(b) Molecular mass of X is less than the molecular mass of Y.
(c) Y is undergoing dissociation in water while X undergoes no change.
(d) X is undergoing dissociation in water.

Q14: Which of the following 0.10 m aqueous solutions will have the lowest freezing point?
(a) Al₂(SO₄)₃
(b) C₆H₁₂O₆
(c) KCl
(d) C₁₂H₂₂O₁₁

Q15: If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution, the change in freezing point of water (ΔT_f), when 0.01 mol of sodium sulphate is dissolved in 1 kg of water, is (K_f = 1.86 K·kg·mol⁻¹):
(a) 0.372 K
(b) 0.0558 K
(c) 0.0744 K
(d) 0.0186 K

Q16: Which one of the following salts will have the same value of van’t Hoff factor (i) as that of K4[Fe(CN)6].
(a) Al₂(SO₄)₃
(b) NaCl
(c) Al(NO₃)₃
(d) Na₂SO₄.

Q17: Mole fraction of the solute in a 1.00 molal aqueous solution is:
(a) 0.1770
(b) 0.0177
(c) 0.0344
(d) 1.7700

Q18: 25.3 g of sodium carbonate (Na₂CO₃) is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentrations of sodium ions (Na⁺) and carbonate ions (CO₃²⁻), respectively, are (Molar mass of Na₂CO₃ = 106 g·mol⁻¹):
(a) 0.955 M and 1.910 M
(b) 1.910 M and 0.955 M
(c) 1.910 M and 1.910 M
(d) 0.477 M and 0.477 M

Q19: Azeotropic mixture of HCl and H₂O has:
(a) 48% HCl
(b) 22.2% HCl
(c) 20.2% HCl
(d) None of these

Q20: Which of the following statements, regarding the mole fraction (x) of a component in solution, is incorrect?
(a) 0 < x < 1
(b) x < 1
(c) x is always non-negative
(d) –2 < x < 2

Q21: Coolant used in car radiator is aqueous solution of ethylene glycol. In order to prevent the solution from freezing at -0.3°C, how much ethylene glycol (in g) must be added to 5 kg of water? (K_f = 1.86 K·kg·mol⁻¹)

Q22: What is the degree of dissociation of sodium chloride if the molar mass determined by a cryoscopic method was found to be 31.80 g·mol⁻¹?
[Atomic mass: Na = 23 g·mol⁻¹, Cl = 35.5 g·mol⁻¹]?

Q23: A 0.0020 m aqueous solution of an ionic compound Co(NH₃)₅(NO₂)Cl freezes at – 0.00732 °C. Number of moles of ions which 1 mol of ionic compound produces on being dissolved in water will be (K_f = – 1.86 °C/m)

Q24: A solution of urea (molar mass = 56 g mol⁻¹) boils at 100.18°C at the atmospheric pressure. If K_f and K_b for water are 1.86 and 0.512 K kg mol⁻¹, respectively, calculate the temperature (in °C) at which the above solution will freeze.

Q25: Freezing point of an aqueous solution is -0.186°C. If the values of K_f and K_b for water are 1.86 K·kg·mol⁻¹ and 0.52 K·kg·mol⁻¹, respectively, then the elevation of boiling point of the solution (in K) is: