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

$A$ molecule $M$ associates in a given solvent according to the equation $M \rightleftharpoons (M)_n$. For a certain concentration of $M,$ the van't Hoff factor was found to be $0.9$ and the fraction of associated molecules was $0.2.$ The value of $n$ is

$2 \ g$ of benzoic acid $(M_w = 122 \ g/mol)$ dissolved in $25 \ g$ of $C_6H_6$ shows a depression in freezing point equal to $1.62 \ K$. Given $K_f (C_6H_6) = 4.9 \ K \ kg \ mol^{-1}$. If the acid forms a dimer in the solution,then the percentage association of the acid is $......... \%$.

The observed and calculated molecular weights of calcium nitrate are $65.6$ and $164$ respectively. The degree of dissociation of calcium nitrate is .......... $\%$.

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

In an experiment to estimate the molecular weight of benzoic acid by the elevation in boiling point method,the experimental value of the molecular weight was double the actual value. Calculate the degree of association of the dimer.