QJEEAdv19Ch3ba6: JEE Advanced 2019 Chemistry - Class 12 JEEAdv19Ch3ba6 Solution: Fusion of MnO 2 with KOH in presence of O 2 produces a salt W.…

$$Mn{O}_4^{2-}$$ ion has one unpaired electrons, therefore it gives d-d transition to form green colour. Y complex has paramagnetic nature due to presence of one unpaired electron.

In aqueous solution,



$$Mn{O}_4^{2-}$$ ions gives charge transfer spectrum in which a fraction of electronic charge is transferred between the molecular entities.

$$\because$$ $$\underset{(Y)}{Mn{O}_4^{2-}}\underset{oxidation}{\overset{Electrolytic}{⟶}}\underset{(Z)}{Mn{O}_4^{-}}+e^{-}$$

In acidic medium, Y undergoes disproportionation reaction.



$$\underset{(Y)}{Mn{O}_4^{2-}}$$ and $$\underset{(Z)}{Mn{O}_4^{-}}$$ both ions form $$\pi$$-bonding between p-orbitals of oxygen and d-orbitals of manganese.

Thus, options (a, c, d) are correct.