Q.1 An aqueous solution of hydrochloric acid

Options:
(a) Obeys Raoult’s law
(b) Shows negative deviation from Raoult’s law
(c) Shows positive deviation from Raoult’s law
(d) Obeys Henry’s law at all compositions

Answer=B

Q.2 Exactly 1 g of urea dissolved in 75 g of water gives a solution that boils at 100.114°C at 760 torr. The molecular weight of urea is 60.1. The boiling point elevation constant for water is

Options:
(a) 1.02 (b) 0.51
(c) 3.06 (d) 1.51

Answer=B

Q.3 12g of urea is dissolved in 1 litre of water and 68.4 g of sucrose is dissolved in 1 litre of water. The lowering of vapour pressure of first case is

Options:
(a) equal to second
(b) greater than second
(c) less than second
(d) double that of second

Answer=A

Q.4 At a particular temperature, the vapour pressures of two liquids A and B are respectively 120 and 180 mm of mercury. If 2 moles of A and 3 moles of B are mixed to form an ideal solution, the vapour pressure of the solution at the same temperature will be (in mm of mercury)

Options:
(a) 156 (b) 145
(c) 150 (d) 108

Answer=A

Q.5 The freezing point of equimolal aqueous solution will be highest for

Options:
(a) C₆H₅NH₃ ⁺Cl^–   (b) Ca(NO₃)₂
(c) La(NO₃)₂         (d) C₆H₁₂O₆

Answer=D

Q.6 Which of the following 0.10 m aqueous solutions will have the lowest freezing point ?

Options:
(a) Al₂(SO₄)₃ (b) C₆H₁₂O₆
(c) KCl            (d) C₁₂H₂₂O₁₁

Answer=A

Q.7 A solution containing 10g per dm³ of urea (molecular mass = 60 gmol^–1) is isotonic with a 5% solution of a non volatile solute. The molecular mass of this non volatile solute is

Options:
(a) 300 g mol^–1 (b) 350 g mol^–1
(c) 200 g mol^–1 (b) 250 g mol^–1

Answer=A

Q.8 The vapour pressure of a solvent decreases by 10 mm of Hg when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.2. What should be the mole fraction of the solvent if the decrease in
the vapour pressure is to be 20 mm of Hg ?

Options:
(a) 0.8 (b) 0.6
(c) 0.4 (d) 0.2

Answer=B

Q.9 A solution containing 1.8 g of a compound (empirical formula CH₂O) in 40 g of water is observed to freeze at –0.465° C. The molecular formula of the compound is (K_f of water = 1.86 kg K mol^–1)

Options:
((a) C₂H₄O₂ (b) C₃H₆O₃
(c) C₄H₈O₄ (d) C₆H₁₂O₆

Answer=D

Q.10 Which observation(s) reflect(s) colligative properties?
(i) A 0.5 m NaBr solution has a higher vapour pressure than a 0.5 m BaCl₂ solution at the same temperature
(ii) Pure water freezes at the higher temperature than pure methanol
(iii) a 0.1 m NaOH solution freezes at a lower temperature than pure water

Choose the correct answer from the codes given below

Options:
(a) (i), (ii) and (iii) (b) (i) and (ii)
(c) (ii) and (iii)       (d) (i) and (iii)

Answer=D