Calculate the molar mass of solute in a solution prepared by dissolving 1 gram in $0.3 \mathrm{~dm}^3$ solvent having osmotic pressure 0.2 atm at 300 K.

$$\left[\mathrm{R}=0.082 \mathrm{~dm}^3 \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right]$$

Assuming complete ionisation, arrange the following solutions in order of increasing osmotic pressure.

a) $0.5 \mathrm{~m} \mathrm{~Li}_2 \mathrm{SO}_4$

b) $\mathrm{0.5 ~m~KCl}$

c) $0.5 \mathrm{~m} \mathrm{~Al}_2\left(\mathrm{SO}_4\right)_3$

d) $0.1 \mathrm{~m~BaCl}_2$

Calculate the cryoscopic constant of solvent when 2.5 gram solute is dissolved in 35 gram solvent lowers its freezing point by 3 K. (molar mass of solute is $117 \mathrm{~g} \mathrm{~mol}^{-1}$)

Identify the reason for the solubility of polar solute in polar solvent from the following.