(when concentration of different solution is equal)

\(Al_2(SO_4)_3\) provides five ions on ionisation

\(Al_2(SO_4)_3\to 2Al^{3+}\,+\,3SO^{2-}_4\)

while \(KCl\) provides two ions

\(KCl\to K^++Cl^-\)

\(C_6H_{12}O_6\) and \(C_{12}H_{22}O_{11}\) are not ionised so they have single particle in solution.

Hence, \(Al_2(SO_4)_3\) have maximum value of depression in freezing point or lowest freezing point.