For an ideal solution, the non-zero value will be for:

1. \(\Delta H_\text{mix}\)
2. \(\Delta S_\text{mix}\)
3. \(\Delta V_\text{mix}\)
4. \(\Delta P=P_{\text{observed}}-P_{\text{Raoult}}\)

An aqueous solution is 1.00 molal in KI. The vapour pressure of the solution can be increased by:

1. Addition of NaCl

2. Addition of Na₂SO₄

3. Addition of 1.00 molal Kl

4. Addition of water

A solution containing 10 g/dm³ of urea (molecular mass = 60 g mol^-1) is isotonic with a 5 % solution of a non-volatile solute. The molecular mass of this non-volatile solute is:

1.00 g of non-electrolyte solute (molar mass 250 g mol^-1) was dissolved in 51.2 g of benzene. If the freezing point depression constant, K_f of benzene is 5.12 mol^-1 kg K, the freezing point of benzene will be lowered by:

1. 0.4 K

2. 0.3 K

3. 0.5 K

4. 0.2 K

The mixture among the following that forms maximum boiling azeotrope is:

1. Heptane + Octane
2. Water + Nitric acid
3. Ethanol + Water
4. Acetone + Carbon disulphide

Consider the following statements about the composition of the vapour over an ideal 1:1 molar mixture of benzene and toluene. The correct statement is:

Assume that the temperature is constant at 25 ^oC.
(Given, vapour pressure data at 25 °C, benzene = 12.8 kPa, toluene = 3.85 kPa)

If the molality of the dilute solution is doubled, the value of molal depression constant (K_f) will be-
1. Halved
2. Tripled
3. Unchanged
4. Doubled

The equal weight of a solute is dissolved in an equal weight of two solvents A and B to form a very dilute solution. The relative lowering of vapour pressure for solution B has twice the relative lowering of vapour pressure for solution A.

If ${\mathrm{M}}_{\mathrm{A}}$ and ${\mathrm{M}}_{\mathrm{B}}$ are the molecular weights of solvents A and B respectively, then:

1. ${\mathrm{M}}_{\mathrm{A}}$ = ${\mathrm{M}}_{\mathrm{B}}$

2. ${\mathrm{M}}_{\mathrm{B}}$ = 2${\mathrm{M}}_{\mathrm{A}}$

3. ${\mathrm{M}}_{\mathrm{A}}$ = 4${\mathrm{M}}_{\mathrm{B}}$

4. ${\mathrm{M}}_{\mathrm{A}}$ = 2${\mathrm{M}}_{\mathrm{B}}$

A 500 g toothpaste sample has 0.4 g fluoride concentration. The fluoride concentration in terms of ppm will be -