When substance $A$ is dissolved in solvent $B$,it associates to form $A_3$. The van't Hoff factor $i$ is:

The molecular weight of benzoic acid in benzene as determined by the depression in freezing point method corresponds to:

When $20 \ g$ of naphthoic acid $(C_{11}H_8O_2)$ is dissolved in $50 \ g$ of benzene, a freezing point depression of $2 \ K$ is observed. The van't Hoff factor $(i)$ is [$K_f = 1.72 \ K \ kg \ mol^{-1}$].

In a solution of sulfur in carbon disulfide,$80 \%$ of the sulfur exists as $S_8$ and the remaining exists as $S_2$. The van't Hoff factor '$i$' will be:

$A$ $0.004 \ M$ solution of $Na_2SO_4$ is isotonic with a $0.010 \ M$ solution of glucose at the same temperature. The apparent degree of dissociation of $Na_2SO_4$ is $..... \ \%$.

The van't Hoff factor $i$ for a compound which undergoes dissociation in one solvent and association in another solvent is respectively: