The observed molar mass determined for $Na_2SO_4$ by the freezing point depression method is $50.0 \ g/mol$. The theoretical molar mass of $Na_2SO_4$ is $142 \ g/mol$. What will be the degree of dissociation $\alpha$ for $Na_2SO_4$ in water?

$0.2$ molal aqueous solution of $KCl$ freezes at $-0.680^{\circ} C$. Calculate van't Hoff factor for this solution. $(K_{f} = 1.86 \ K \ kg \ mol^{-1})$

Select the correct statement for the van't Hoff factor $(i)$ of benzoic acid in benzene.

Which of the following expressions correctly defines the Van't Hoff factor $i$?

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 ........ .

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