$2.0 \, m \, CH_3COOH$ undergoes $100 \%$ dimerization in benzene. It will be isotonic with which of the following?

$A$ solution containing $10 \ g$ of an electrolyte $AB_2$ in $100 \ g$ of water boils at $100.52^{\circ} C$. The degree of ionization of the electrolyte $(\alpha)$ is............ $\times 10^{-1}$.
(nearest integer)
[Given : Molar mass of $AB_2 = 200 \ g \ mol^{-1}$,$K_{b}$ (molal boiling point elevation constant of water) $= 0.52 \ K \ kg \ mol^{-1}$,boiling point of water $= 100^{\circ} C$;
$AB_2$ ionises as $AB_2 \rightarrow A^{2+} + 2B^{-}$]

Two solutions of $KNO_3$ and $CH_3COOH$ are prepared separately. Molarity of both is $0.1 \ M$ and osmotic pressures are $P_1$ and $P_2$ respectively. The correct relationship between the osmotic pressures is :-

The interionic attraction depends on the interaction of:

If $A_2 B$ is $30 \%$ ionised in an aqueous solution,then the value of van't Hoff factor $(i)$ is $............ \times 10^{-1}$.

What is the expected value of $\Delta T_f$ for $1.25 \ m$ $CaCl_2$ solution if $1.25 \ m$ sucrose solution has $\Delta T_f$ value $x \ K$?