If the density of lake water is 1.25 g mL^–1 and contains 92 g of Na⁺ ions per kg of water, then the molality of Na⁺ ions will be-

1.	3.24 molal	2.	4 molal
3.	5 molal	4.	3.5 molal

The Vapour pressure of water at 293 K is 17.535 mm Hg. The vapour pressure of water at 293 K when 25 g of glucose is dissolved in 450 g of water is-

1. 18.54 mm of Hg

2. 17.44 mm of Hg

3. 12.35 mm of Hg

4. 18.67 mm of Hg

Benzene and toluene form an ideal solution over the entire range of composition. The vapour pressure of pure benzene and toluene at 300 K are 50.71 mm Hg and 32.06 mm Hg respectively.

The mole fraction of benzene in vapour phase, if 80 g of benzene is mixed with 100 g of toluene, would be -

1. 0.41

2. 0.68

3. 0.72

4. 0.59

The osmotic pressure of a solution prepared by dissolving 25 mg of K₂SO₄ in 2 litres of water at 25° C, assuming that it is completely dissociated is-

 $1. 2.76 \times {10}^{-3} \mathrm{atm}$
$2. 5.39 \times {10}^{-4} \mathrm{atm}$
$3. 5.27 \times {10}^{-3} \mathrm{atm}$
$4. 3.19 \times {10}^{-3} \mathrm{atm}$

Mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride is

1. 0.46

2. 0.54

3. 0.27

4. 0.35

What is the mass of urea (NH₂CONH₂) required in making 2.5 kg of 0.25 molal aqueous solution?

1. 74 g

2. 69 g

3. 33 g

4. 37 g

What is the molarity of KI if density of 20% (mass/mass) aqueous KI is 1.202 g mL^-1?

1. 1.23 mol L^-1

2. 1.45 mol L^-1

3. 1.62 mol L^-1

4. 1.45 mol mL^-1

H₂S, a toxic gas with rotten egg like smell, is used for the qualitative analysis. If the solubility of H₂S in water at STP is 0.195 molal, what is the Henry’s law constant?

1. 255 bar

2. 293 bar

3. 342 atm

4. 282 bar

Henry’s law constant for CO₂ in water is 1.67 × 10⁸ Pa at 298 K. What is the quantity of CO₂ in 500 mL of soda water when packed under 2.5 atm CO₂ pressure at 298 K?

1. 1.57 g

2. 1.85 g

3. 0.15 g

4. 1.96 g

Boiling point of water at 750 mm Hg is 99.63°C. How much sucrose is to be added to 500 g of water such that it boils at 100°C?

 ( K_b H₂O = 0.52 K kg mol⁻¹)

^{1. 134.76g}

^{2. 121.67g}

^{3. 145.14g}

^{4. 124.79g}