A solution containing 3.3 g of a substance in 125 g of benzene (b.p. 80°C) boils at 80.66°C. If K_b for one litre of benzene is 3.28°C, the molecular weight of the substance shall be 

1. 127.20

2. 131.20

3. 137.12

4. 142.72

The molal b.p. constant for water is $0{.513}^{o}Ckgmo{l}^{-1}$. When 0.1 mole of sugar is dissolved in 200 g of water, the solution boils under a pressure of 1 atm at

(1) 100.513°C

(2) 100.0513°C

(3) 100.256°C

(4) 101.025°C

What is the molality of the solution of a certain solute in a solvent if there is a freezing point depression of 0.184° and if the freezing point constant is 18.4 K kg mol⁻¹

1. 0.01

2. 1.00

3. 0.001

4. 100

The molar freezing point constant for water is 1.86°C/mole. If 342 g of cane sugar $\left({\mathrm{C}}_{12}{\mathrm{H}}_{22}{\mathrm{O}}_{11}\right)$ is dissolved in 1000 g of water, the solution will freeze at 

1. –1.86°C

2. 1.86°C

3. –3.92°C

4. 2.42°C

The depression in freezing point of 0.01 M aqueous solutions of urea, sodium chloride and sodium sulphate is in the ratio of [Roorkee 1990; DCE 1994]

(1) 1 : 1 : 1

(2) 1 : 2 : 3

(3) 1 : 2 : 4

(4) 2 : 2 : 3

The Van't Hoff factor for 0.1 M $\mathrm{Ba}{\left({\mathrm{NO}}_3\right)}_2$ solution is 2.74. The degree of dissociation is [IIT 1999]

(1) 91.3%

(2) 87%

(3) 100%

(4) 74%

The osmotic pressure of 5 % (mass-volume) solution of cane sugar at 150 °C (mol. mass of sugar = 342 g/mole) is:

Osmotic pressure is 0.0821 atm at a temperature of 300 K. Find concentration in mole/litre [Roorkee 1990]

(1) 0.033

(2) 0.066

(3) 0.33 × 10^–2

(4) 3

The vapour pressure of a solvent A is 0.80 atm. When a non-volatile substance B is added to this solvent its vapour pressure drops to 0.6 atm. The mole fraction of B in the solution is [MP PMT 2000]

(1) 0.25

(2) 0.50

(3) 0.75

(4) 0.90

Volume of 10 M HCl should be diluted with water to prepare 2.00 L of 5 M HCl is 

(1) 2 L

(2) 1.5 L

(3) 1.00 L

(4) 0.5 L