If the relative decrease in vapour pressure is 0.4 for a solution containing 1 mol NaCl in 3 mol of ${\mathrm{H}}_2\mathrm{O}$, then percentage ionisation of NaCl will be -

1. 60%

2. 80%

3. 40%

4. 100%

The Henry's law constant for the solubility of N₂ gas in water at 298 K is 1.0 × 10⁵ atm. The mole fraction of N₂ in air is 0.8. The number of moles of N₂ formed from air dissolved in 10 moles of water at 298 K and 5 atm pressure is-

When 20 g of naphthoic acid (C₁₁H₈O₂) is dissolved in 50 g of benzene (K_f = 1.72 K kg mol^–1),
a freezing point depression of 2 K is observed. The van’t Hoff factor (i) is –

Aqueous solutions of 0.004 M Na₂SO₄ and  0.01 M Glucose are isotonic. The degree of dissociation of Na₂SO₄ is-

1. 25% 

2. 60%

3. 75% 

4. 85%

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

The correct statement regarding a solution of two components A and B exhibiting positive deviation from ideal behaviour is :

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

For an ideal solution, the correct option is -

1. ${∆}_{\mathrm{mix}}$ $\mathrm{G}=0$ at constant T and P

2. ${∆}_{\mathrm{mix}}$ $\mathrm{S}=0$ at constant T and P

3. ${∆}_{\mathrm{mix}}$ $\mathrm{V}\ne 0$ at constant T and P

4. ${∆}_{\mathrm{mix}}$ $\mathrm{H}=0$ at constant T and P

During osmosis, the flow of water through a semi-permeable membrane 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