Calculate the number of moles of nonvolatile solute dissolved in 0.5 kg solvent if molal elevation constant for solvent is $2 \mathrm{~kg} \mathrm{~K} \mathrm{~mol}^{-1} \left[\Delta \mathrm{T}_{\mathrm{b}}=0.8 \mathrm{~K}\right]$

Arrange the following equimolar solutions according to increasing order of osmotic pressure [Assume complete ionisation]

i) KCl

ii) $\mathrm{BaCl}_2$

iii) $\mathrm{AlCl}_3$

iv) $\mathrm{Al}_2\left(\mathrm{SO}_4\right)_3$

Which from following pairs of solutions in water exhibits same osmotic pressure at same temperature?

[molar mass of urea $=60 \mathrm{~g} \mathrm{~mol}^{-1}$, sucrose $=342 \mathrm{~g} \mathrm{~mol}^{-1}$ ]

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 $1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$.