When 0.1 m CH₃COOH is present in a solvent it shows elevation in boiling point of 0.75$°\mathrm{C}$. Acid dissociation constant will be -(K_b=5 K Kg mol^-1) (1M =1m)

(1) 5 X 10^-2

(2) 5 X 10^-3

(3) 10^-2

(4) 10^-3 

Which of the following pairs exhibit positive deviation from Raoult's law?
 

(i) Chloroform and Acetone

(ii) Carbon disulphide and Acetone

(iii) Ethanol and Acetone

(iv) Phenol and Aniline

1. i and ii

2. ii and iii

3. i and iv

4. ii and iv

A non-volatile solute is dissolved in water. If its degree of association is 50%. What will be its freezing point when the boiling point is 100.52$°\mathrm{C}$. [K_b=0.52 K kg mol^-1, K_f=1.86K kg mol^-1]

1. -0.52 K

2. -0.52$°\mathrm{C}$

3. -1.86$°\mathrm{C}$

4. 275.01 K

Calculate the molecular formula of a solute having the empirical formula CH₂O if 36 g of the solute, dissolved in 1.2 kg of water, lowers the freezing point to −0.93°C.

Given: Kf of water = 1.86 K kg mol⁻¹.

1. C₂H₄O

2. C₂H₂O₂

3. C₂H₄O₃

4. C₂H₄O₂

If partial pressure of oxygen is 0.5 atm and K_H = 1.4 × 10^-3 M/atm, then the amount of oxygen dissolved in 100 ml water at 298K is-

A solute x when dissolved in solvent associates to form a pentamer. The value of van't hoff factor (i) for the solute will be:-

1. 0.5

2. 5

3. 0.2

4. 0.1

Calculate the amount of CaCl₂ needed to be dissolved in 2 L of water so that the solution shows an
 osmotic pressure of 0.5 atm at 27°C, given i = 2.47.

1. 13.42 g

2. 19.24 g

3. 8.834 g

4. 1.820 g

One litre aqueous solution of sucrose (molar mass = 342 g/mol) weighing 1015 g is found to record an osmotic pressure of 4.8 atm at 293K. What is the molality of the sucrose solution ? (R= 0.0821 L atm K^-1 mol^-1) :

(1) 0.84

(2) 0.21

(3) 0.42

(4) 0.63

The total vapour pressure of an ideal solution containing volatile liquids A and B is 600 torr. The mole fraction of A is 0.70 in the liquid phase and 0.35 in the vapour phase. Calculate the vapour pressures of pure A and pure B, respectively.

1.  300 torr, 130 torr

2.  1300 torr, 130 torr

3. 300 torr, 1300 torr

4.  300 torr, 300 torr

What is the vapour pressure of a solution when the mole fraction of water is 0.9, assuming the vapor pressure of pure water is 30 mm Hg at room temperature?

1. 30 mm of Hg

2. 24 mm of Hg

3. 21 mm of Hg

4. 27 mm of Hg