Calculate the boiling point elevation of solution if 15 g urea is dissolved in 1000 g water. $\left[\mathrm{K}_{\mathrm{b}}\right.$ for water $=0.52 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$; molar mass of urea $=60 \mathrm{~g} \mathrm{~mol}^{-1}$ ]

Arrange the following solutions according to decreasing order of osmotic pressure under similar condition of temperature and assuming complete dissociation.

$$ \begin{array}{|c|l|} \hline \text { I. } & 0.2 \mathrm{~m} \mathrm{KCl} \\ \hline \text { II. } & 0.3 \mathrm{~m} \mathrm{MgSO}_4 \\ \hline \text { III. } & 0.1 \mathrm{~m} \mathrm{BaCl}_2 \\ \hline \text { IV. } & 0.5 \mathrm{~m} \mathrm{Al}_2\left(\mathrm{SO}_4\right)_3 \\ \hline \end{array} $$

Calculate the relative lowering of vapour pressure of solution containing 0.56 g nonvolatile solute in 100 g water [molar mass of solute $=60 \mathrm{~g} \mathrm{~mol}^{-1}$ ]

Which of the following aqueous solutions exhibits lowest freezing point depression assuming complete dissociation?