Fusion of `MnO_2` with KOH in the presence of `O_2` produces a salt W. Alkaline solution of W upon electrolytic oxidation yields another salt X. The manganese containing ions present in W and X, respectively, are Y and Z. Correct statement(s) is (are)

Options

A. in both Y and Z, `pi`-bonding occurs between p-orbitals of oxygen and d-orbitals of manganese
B. both Y and Z are coloured and have tetrahedral shape
C. in aqueous acidic solution, Y undergoes disproportionation reaction to give Z and `MnO_2`
D. Y is diamagnetic in nature while Z is paramagnetic.

Answer

A, B, C

Explanation

`2MnO_2 + 4KOH +O_2 overset("fusion")(to) underset("green colour")(2K_2MnO_4 + 2H_2O)`
On electrolysis of `K_2MnO_4, MnO_4^(2-)` gest oxidises to `MnO_4^-`
`2K_2MnO_4 + 2H_2O overset("electrolysis")(to) 2KMnO_4 + 2kOH + H_2`
`K_2MnO_4` is in neutral or acidic medium undergoes disproportionation.
`3MnO_4^(2-) + 4H^(+) to 2MnO_4^(-) + MnO_2 + 2H_2O`
`K_2MnO_4` is green in colour and `KMnO_4` is purple in colour . both are tetrahedral in shape and involve `p pi - d pi ` bonding .
`Y (MnO_4^(2-))` is paramagnetic while `Z(MnO_4^-)` is diamagnetic in nature .