The freezing point of an aqueous solution of `KCN` containing `0.1892 mol kg^(-1)` was `-0.704^(circ)C`. On adding `0.45` mole of `Hg(CN)_(2)`, the freezing point of the solution was `=0.620^(circ)C`. If whole of `Hg(CN)_(2)` is used in complex formation according to the equation,
`Hg(CN)_(2)+mKCN rarrK_(m)[Hg(CN)_(m+2)]`
what is the formula of the complex ? Assume `[Hg(CN)_(m+2)]^(m-)` is not ionised and the complex molecule is `100%` ionised. `(K_(f)(H_(2)O)` is `1.86 kg mol^(-1) K`.)
