Chemistry - Liquid Solution Question with Solution | TestHub

The elevation in boiling point is a colligative property and is given by the expression $\Delta T_b=i{K}_{b}m$.

For equimolar solutions, the molality $m$ is constant. Therefore, the elevation in boiling point is directly proportional to the van't Hoff factor $i$ (number of ions produced per formula unit upon complete dissociation).

Calculating the van't Hoff factor $i$ for each compound assuming complete dissociation:

Potassium chloride ($KCl$) $\to K^{+}+C{l}^{-}$ ($i=2$)

Lithium sulfate ($L{i}_{2}S{O}_4$) $\to 2L{i}^{+}+S{O}_4^{2-}$ ($i=3$)

Aluminium sulphate ($A{l}_2(S{O}_4{)}_3$) $\to 2A{l}^{3+}+3S{O}_4^{2-}$ ($i=5$)

Ammonium phosphate ($(N{H}_4{)}_{3}P{O}_4$) $\to 3N{H}_4^{+}+P{O}_4^{3-}$ ($i=4$)

Since Aluminium sulphate has the maximum value of $i$, it produces the maximum number of particles in solution and thus exhibits the maximum boiling point elevation.

Answer: Aluminium sulphate .