Chemistry - Complete d-block Question with Solution | TestHub

${\mathrm{MnO}}_2+2\mathrm{KOH}+\frac{1}{2}{\mathrm{O}}_2\stackrel{\Delta }{\to }\underset{(\mathrm{W})}{{\mathrm{K}}_2{\mathrm{MnO}}_4}+{\mathrm{H}}_2\mathrm{O}$

$$\begin{array}{rlrlr}& \left[(\mathrm{W})={\mathrm{K}}_2{\mathrm{MnO}}_{4(\mathrm{aq})}\rightleftharpoons 2{\mathrm{K}}_{(\mathrm{aq})}^{\oplus }+\underset{(\mathrm{Y})}{{\mathrm{MnO}}_{4(\mathrm{aq})}^{2\ominus }}\right]& & & \end{array}$$

$$\underset{(\mathrm{W})}{{\mathrm{K}}_2{\mathrm{MnO}}_4}+{\mathrm{H}}_2\mathrm{O}\underset{Redox}{\overset{Electrolytic}{\to }}{\mathrm{H}}_2+\mathrm{KOH}+\underset{(\mathrm{X})}{{\mathrm{KMnO}}_4}$$

$$\left[anionof\mathrm{X}=\underset{(\mathrm{Z})}{{\mathrm{MnO}}_4^{\ominus }}\right]$$

$$\left[\because \underset{(\mathrm{Y})}{{\mathrm{MnO}}_4^{2\ominus }}\underset{Oxidation}{\overset{Electrolytic}{\to }}\underset{(\mathrm{Z})}{{\mathrm{MnO}}_4^{\ominus }}+{\mathrm{e}}^{\ominus }\right]$$

∵ In acidic solution; Y undergoes disproportionation reaction

$$3{\mathrm{MnO}}_{4(\mathrm{aq})}^{2\ominus }+4{\mathrm{H}}^{\oplus }\to \underset{(\mathrm{Z})}{2{\mathrm{MnO}}_4^{\ominus }}+{\mathrm{MnO}}_2+2{\mathrm{H}}_2\mathrm{O}$$

Hybridization of ${\mathrm{MnO}}_4{}^{-}$and ${\mathrm{MnO}}_4{}^{2-}$ is ${\mathrm{d}}^3\mathrm{s}$