Question

$KMn{O}_4$ acts as an oxidant in neutral, basic and acidic medium. Its final product under these conditions would be respectively:

• A. $Mn{O}_2,Mn{O}_2,M{n}^{2+}$
• B. $Mn{O}_4^{2-},M{n}^{3+},M{n}^{2+}$
• C. $Mn{O}_2,Mn{O}_4^{2-},M{n}^{2+}$
• D. $MnO,Mn{O}_2,M{n}^{2+}$

Answer 1

The correct option is C $Mn{O}_2,Mn{O}_4^{2-},M{n}^{2+}$

The final products obtained from potassium permanganate in the neutral, basic and acidic medium are, $Mn{O}_2,Mn{O}_4^{2-},\text{and}M{n}^{2+}$ respectively.
The respective reactions are shown below,
$Mn{O}_4^{-}+2H_{2}O+3e^{-}\to Mn{O}_2+4O{H}^{-}$
$4Mn{O}_4^{-}+4O{H}^{-}\to 4Mn{O}_4^{2-}+O_2+H_{2}O$
$Mn{O}_4^{-}+8H^{+}+5e^{-}\to M{n}^{2+}+4H_{2}O$