The van't Hoff factor for $BaCl_2$ is $2.47$. Calculate the percentage dissociation of $BaCl_2$ in its aqueous solution. (in $\%$)

When $12.2 \ g$ of benzoic acid is dissolved in $100 \ g$ of water,the freezing point of the solution was found to be $-0.93^{\circ} C$ $(K_{f}(H_{2}O) = 1.86 \ K \ kg \ mol^{-1})$. The number $(n)$ of benzoic acid molecules associated (assuming $100 \ \%$ association) is ........ .

One mole of a solute $A$ is dissolved in a given volume of a solvent. The association of the solute takes place according to $nA \rightleftharpoons (A)_n$. The Van't Hoff factor $i$ is expressed as:

$1.2 \, mL$ of acetic acid is dissolved in water to make $2.0 \, L$ of solution. The depression in freezing point observed for this strength of acid is $0.0198^{\circ} C$. The percentage of dissociation of the acid is $....$ (Nearest integer)
[Given : Density of acetic acid is $1.02 \, g \, mL^{-1}$
Molar mass of acetic acid is $60 \, g \, mol^{-1}$
$K_{f}(H_{2}O) = 1.85 \, K \, kg \, mol^{-1}$]

When benzoic acid dissolves in benzene,the observed molecular mass is

Dimerisation of solute molecules in low dielectric constant solvent is due to