Chemistry - Liquid Solution Question with Solution | TestHub

Osmotic pressure is a colligative property, which depends on the number of solute particles in the solution.

For equimolar solutions, osmotic pressure $\pi \propto i$, where $i$ is the van 't Hoff factor.

Assuming complete ionization, the value of $i$ is equal to the number of ions produced per formula unit:
$\mathrm{KCl}\to {\mathrm{K}}^{+}+{\mathrm{Cl}}^{-}$ ($i=2$)
${\mathrm{BaCl}}_2\to {\mathrm{Ba}}^{2+}+2{\mathrm{Cl}}^{-}$ ($i=3$)
${\mathrm{AlCl}}_3\to {\mathrm{Al}}^{3+}+3{\mathrm{Cl}}^{-}$ ($i=4$)
${\mathrm{Al}}_2({\mathrm{SO}}_4{)}_3\to 2{\mathrm{Al}}^{3+}+3{\mathrm{SO}}_4^{2-}$ ($i=5$)

Since the value of $i$ increases in the order $\mathrm{KCl}<{\mathrm{BaCl}}_2<{\mathrm{AlCl}}_3<{\mathrm{Al}}_2({\mathrm{SO}}_4{)}_3$, the osmotic pressure will also increase in the same order.

Answer: $\mathrm{KCl}<{\mathrm{BaCl}}_2<{\mathrm{AlCl}}_3<{\mathrm{Al}}_2{\left({\mathrm{SO}}_4\right)}_3$