Calculate the relative lowering of vapour pressure if vapour pressure of pure solvent and vapour pressure of solution at $25^{\circ} \mathrm{C}$ are 32 and 30 mm Hg respectively.

Calculate the molality of solution if its depression in freezing point is 0.18 K . $\left[\mathrm{K}_{\mathrm{f}}=1.6 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right]$

Identify the correct statement from following properties.

Calculate van't Hoff factor of 0.15 M solution of electrolyte if it freezes at $-$0.5 K.

$$\left[\mathrm{K}_{\mathrm{f}}=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right]$$