Question

In dilute alkaline solution, $Mn{O}_4^{-}$ changes to:

• A. $Mn{O}^{2-}$
• B. $Mn{O}_2$
• C. $M{n}_2{O}_3$
• D. $MnO$

Answer 1

The correct option is B $Mn{O}_2$

Depending upon the medium, the permaganate ion can be reduced to different species. In a weakly alkaline medium, it is reduced to $Mn{O}_2$.

$Mn{O}_4^{-}+2H_{2}O+3e^{-}\to Mn{O}_2+4O{H}^{-}$(weak alkaline medium)