Chemistry - Liquid Solution Question with Solution | TestHub

Normal molar mass of ${\mathrm{MX}}_2=164.0\mathrm{g}{\mathrm{mol}}^{-1}$ Observed molar mass of ${\mathrm{MX}}_2=65.6\mathrm{g}{\mathrm{mol}}^{-1}$ $\begin{array}{rl}& \text{ Van’t Hoff factor }(\mathrm{i})=\frac{\text{ Normal molar mass }}{\text{ Observed molar mass }}\\ & =\frac{164}{65.6}=2.5\end{array}$ If $\alpha$ is the degree of ionisation, then $\begin{array}{rl}& \underset{1-\alpha }{{\mathrm{MX}}_2}\rightleftharpoons {\mathrm{M}}_{\alpha }^{2+}+\underset{2\alpha }{2{\mathrm{X}}^{-}}\\ & \mathrm{i}=1-\alpha +\alpha +2\alpha =1+2\alpha \\ & 1+2\alpha =2.5\\ & \alpha =0.75\end{array}$ $\therefore$ Percent degree of ionisation $=75\%$