A solution of nonvolatile solute is obtained by dissolving $$15 \mathrm{~g}$$ in $$200 \mathrm{~mL}$$ water has depression in freezing point $$0.75 \mathrm{~K}$$. Calculate the molar mass of solute if cryoscopic constant of water is $$1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$$.

What type of following solutions is the gasoline?

Calculate the relative lowering of vapour pressure if the vapour pressure of benzene and vapour pressure of solution of non-volatile solute in benzene are $$640 \mathrm{~mmHg}$$ and $$590 \mathrm{~mmHg}$$ respectively at same temperature.

Calculate the depression in freezing point of solution when $$4 \mathrm{~g}$$ nonvolatile solute of molar mass $$126 \mathrm{~g} \mathrm{~mol}^{-1}$$ dissolved in $$80 \mathrm{~mL}$$ water [Cryoscopic constant of water $$=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$$ ]