197. Why is Van’t Hoff factor introduced in the equation for colligative properties of solutions?

van’t Hoff factor modifies the equations for colligative
properties as follows:
Relative lowering of vapour pressure of solvent,

$\frac{{\mathrm{p}}_1^0 - {\mathrm{p}}_1}{{\mathrm{p}}_1^0} = i\frac{n_2}{n_1}$

Elevation of Boiling point, ΔTb = i Kb m
Depression of Freezing point, ΔTf = i Kf m
Osmotic pressure of solution, Π = i n2 R T / V
 thus it shows that van't hoff factor depend on solute such that it is a colligative properties.