Abnormal Molar Masses

$1.00$ molal aqueous solution of trichloroacetic acid $\left({\mathrm{CCl}}_3\mathrm{COOH}\right)$ is heated to its boiling point. The solution has a boiling point of $100.18°\mathrm{C}$. Determine the van’t Hoff factor for trichloroacetic acid (${\mathrm{K}}_{\mathrm{b}}$ for water =$0.512\mathrm{K} \mathrm{kg} {\mathrm{mol}}^{-1}$).

Define the following term :

Van't Hoff factor