Which of the following statements concerning the properties of solutions describes a colligative effect?

$A$ substance '$X$' $(1.5 \ g)$ dissolved in $150 \ g$ of a solvent '$Y$' (molar mass $= 300 \ g \ mol^{-1}$) led to an elevation of the boiling point by $0.5 \ K$. The relative lowering in the vapour pressure of the solvent '$Y$' is . . . . . . $\times 10^{-2}$. (Nearest integer)
[Given : $K_{b}$ of the solvent $= 5.0 \ K \ kg \ mol^{-1}$]
Assume the solution to be dilute and no association or dissociation of $X$ takes place in solution.

At $35^{\circ} C$,the vapour pressure of $CS_{2}$ is $512 \; mm \; Hg$ and that of acetone is $344 \; mm \; Hg$. $A$ solution of $CS_{2}$ in acetone has a total vapour pressure of $600 \; mm \; Hg$. The false statement amongst the following is

Solid Lead nitrate is dissolved in $1 \, L$ of water. The solution was found to boil at $100.15^{\circ}C$. When $0.2 \, mol$ of $NaCl$ is added to the resulting solution,it was observed that the solution froze at $-0.8^{\circ}C$. The solubility product of $PbCl_2$ formed is $........... \times 10^{-6}$ at $298 \, K$. (Nearest integer) Given: $K_b = 0.5 \, K \, kg \, mol^{-1}$ and $K_f = 1.8 \, K \, kg \, mol^{-1}$. Assume molality to be equal to molarity in all cases.

$A$ liquid freezes at $7^{\circ} C$ and boils at $77^{\circ} C$. If $K_{f}$ and $K_{b}$ values for the liquid are $5.6$ and $2.5 \ ^{\circ} C \ kg \ mol^{-1}$ respectively,then the ratio of latent heat of vaporisation of the liquid to the latent heat of fusion is $:-$

Pick the correct statement.