A solution of 5 g nonvolatile solute in 50 g water decreases its freezing point by 0.2 K . Calculate the molar mass of solute if $\mathrm{K}_{\mathrm{f}}$ of water is $1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$.

Calculate the molality of the solution containing nonvolatile solute if boiling point elevation of solution is 0.39 K .

[ $\mathrm{K}_{\mathrm{b}}$ of water $=0.52 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$ ]

Calculate the cryoscopic constant of solvent if depression in freezing point of 0.4 m solution of nonvolatile solute is 1.8 K .

Which from following mixtures obeys Raoult's law?