In a solution with molality $m$,if the solute exists as a trimer,what would be the depression in the freezing point of the solution?

Benzoic acid molecules undergo dimerisation in benzene. $2.44 \ g$ of benzoic acid when dissolved in $30 \ g$ of benzene caused a depression in freezing point of $2 \ K$. What is the percentage of association of it? (Given $K_f(C_6H_6) = 5 \ K \ kg \ mol^{-1}$; molar mass of benzoic acid $= 122 \ g \ mol^{-1}$)

$1.2 \, mL$ 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 $60 \, g \, mol^{-1}$
$K_{f}(H_{2}O) = 1.85 \, K \, kg \, mol^{-1}$]

Pure benzene freezes at $5.3^oC$. $A$ solution of $0.223 \ g$ of $C_6H_5CH_2COOH$ in $4.49 \ g$ of benzene freezes at $4.47^oC$. Given $K_f = 5.12 \ K \ kg/mol$,what can be concluded from this?

$A$ $0.5\%$ solution of potassium chloride was found to freeze at $-0.24^{\circ} C$. The percentage dissociation of potassium chloride is .... (Nearest integer)
(Molal depression constant for water is $1.80\, K\, kg\, mol^{-1}$ and molar mass of $KCl$ is $74.6\, g\, mol^{-1}$)

The molecular weight of benzoic acid dissolved in benzene is found to be ............ $g/mol$.