What mass of urea is needed to prepare 2.5 kg of a 0.25 m aqueous solution?

1.	73 g	2.	37 g
3.	48 g	4.	24 g

The molarity of a 20% (mass/mass) KI solution with a density of 1.202 g/mL will be:

1. 2.34 M

2. 1.45 M

3. 3.32 M

4. 0.23 M

The solubility of H₂S in water at STP is 0.195 m. The value of Henry's constant is-

A solution is obtained by mixing 300 g of 25% solution and 400 g of 40% solution by mass. The mass percentage of the solvent in resulting solution is:

1. 66.43 %

2. 36.54 %

3. 12.45 %

4. 33.97 %

The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350 K. The composition of the liquid mixture if total vapour pressure is 600 mm Hg is:

$1. {\mathrm{x}}_{\mathrm{A}} =0.2 ; {\mathrm{x}}_{\mathrm{B} }= 0.8$
$2. {\mathrm{x}}_{\mathrm{A}} = 0.8 ; {\mathrm{x}}_{\mathrm{B}} = 0.2$
$3. {\mathrm{x}}_{\mathrm{A} }= 0.4 ; {\mathrm{x}}_{\mathrm{B}} = 0.6$
$4. {\mathrm{x}}_{\mathrm{A} }= 0.6 ; {\mathrm{x}}_{\mathrm{B} }= 0.4$
$$

The vapour pressure of water in the solution having 50 g of urea dissolved in 850 g of water is-

(Vapor pressure of pure water at 298 K is 23.8 mm Hg) 

1. 23.40 mm of Hg

2. 33.46 mm of Hg

3. 12.76 mm of Hg

4. 87.12 mm of Hg

The amount of sucrose is to be added to 500 g of water such that it boils at 100°C is:

( Given: The boiling point of water at 750 mm Hg is 99.63°C ; K_b = 0.52 K kg mol^-1)

1. 145.76 g

2. 213.54 g

3. 121.67 g

4. 195.36 g

The solubility of a gas in a liquid decreases with an increase in temperature because:

To minimize the painful effects accompanying deep sea diving, oxygen diluted with less soluble helium gas is used as breathing gas by the divers. This is an example of the application of: