The molal 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 Ba(NO₃)₂ solution is 2.74. The degree of dissociation is -

1. 91.3 %

2. 87 %

3. 100 %

4. 74 %

The latent heat of vaporization of water is 540 cal g^-1 at 100 ^oC. K_b for water is:

1. $0.562 \mathrm{K }{m}^{-1}$

2. $1.86 \mathrm{K }{m}^{-1}$

3. $0.515 \mathrm{K }{m}^{-1}$

4. $5.12 \mathrm{K }{m}^{-1}$

The molality of a solution containing a certain solute, if there is a freezing point depression of 0.184 °C, is-

(K_f = 18.4)

1. 0.01 m

2. 10 m

3. 0.05 m

4. 100 m

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

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 m^-1, the molecular weight of the substance shall be -

1. 127.20 g mol^-1

2. 131.20 g mol^-1

3. 137.12 g mol^-1

4. 142.72 g mol^-1

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

1. 4 atm

2. 5.07 atm

3. 3.55 atm

4. 2.45 atm

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