Which from following mixtures obeys Raoult's law?

Calculate the osmotic pressure of 0.2 M aqueous solution of electrolyte at 300 K . If van't Hoff factor is $1.6\left[\mathrm{R}=0.0821 \mathrm{~atm} \mathrm{dm} \mathrm{K}^{-1} \mathrm{~mol}^{-1}\right]$.

Determine the expected value of $\Delta T_f$ for $1 \mathrm{~m} \mathrm{CaCl}_2$ solution if 1 m urea solution has $\Delta \mathrm{T}_{\mathrm{f}}$ value ' $x$ ' K .

Calculate van't Hoff factor of aqueous solution of 0.18 m electrolyte that freezes at $-0.54^{\circ} \mathrm{C}$.

$\left(\mathrm{K}_{\mathrm{f}}\right.$ for solvent $\left.=1.86 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right)$