$\mathrm{MnO}_{4}^{2-}$, in acidic medium, disproportionates to :

(C) $\mathrm{MnO}_{4}^{-}$ and $\mathrm{MnO}_{2}$

(A) $\mathrm{Mn}_{2} \mathrm{O}_{7}$ and $\mathrm{MnO}_{2}$

(B) $\mathrm{MnO}_{4}^{-}$ and MnO

(D) $\mathrm{Mn}_{2} \mathrm{O}_{7}$ and MnO

JEE Main · 2026 · 21 Jan 2026 · Shift 1 · d and f Block Elements

MnO_{4}^{2 -}

, in acidic medium, disproportionates to :

Answer: (C)

In acid the manganate ion is unstable and disproportionates, the manganese going from

+ 6

both up to

+ 7

and down to

+ 4

3 Mn O_{4}^{2 -} + 4 H^{+} \to 2 Mn O_{4}^{-} + Mn O_{2} + 2 H_{2} O

. The products are the permanganate ion, MnO

_{4}^{-}

, and manganese dioxide, MnO

_{2}

JEE Main · 2026 · 21 Jan 2026 · Shift 1 · Single correct option