When $1.0 \ g$ of $KCl$ is dissolved in $200 \ g$ water,the decrease in freezing point of such solution is $0.24 \ K$,calculate Van't Hoff factor $(i)$ for such solution. $K_f$ of water $=$ $1.86 \ K \ kg \ mol^{-1}$.

The freezing point of benzene decreases by $0.45 ^\circ C$ when $0.2 \ g$ of acetic acid is added to $20 \ g$ of benzene. If acetic acid associates to form a dimer in benzene,the percentage association of acetic acid in benzene will be .......... $\%$
$(K_f \text{ for benzene} = 5.12 \ K \ kg \ mol^{-1})$

If a solute associates in a solvent, its experimentally calculated molar mass using the boiling point elevation method will be

Assertion : Molecular mass of benzoic acid when determined by colligative properties is found high.
Reason : Dimerisation of benzoic acid.

The observed and calculated molecular weights of calcium nitrate are $65.6$ and $164$ respectively. The degree of dissociation of calcium nitrate is .......... $\%$.

$75.2 \ g$ of phenol is added to $1 \ kg$ of solvent. The depression in freezing point is $7 \ K$. If phenol undergoes dimerization,calculate the percentage of association. $(K_f = 14 \ K \ kg \ mol^{-1})$