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

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

Calculate the relative lowering of vapour pressure of solution containing 46 g of non volatile solute in 162 g of water at $20^{\circ} \mathrm{C}$. [Molar mass of nonvolatile solute $=46 \mathrm{~g} \mathrm{~mol}^{-1}$]

Calculate molar mass of a solute at 300 K if 400 mg of it is dissolved in 300 mL of water exerts osmotic pressure of 0.2 atm .

$$\left(\mathrm{R}=0.0821 \mathrm{~L} \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$$

What is the vapour pressure of a solution containing 0.1 mol of non volatile solute dissolved in 16.2 g water? $\left(\mathrm{P}_1^0=24 \mathrm{mmHg}\right.$, molar mass of water $18 \mathrm{~g} \mathrm{~mol}^{-1}$ )