Question

The number of electrons involved in the conversion of $Mn{O}_4^{-}$, to $Mn{O}_2$ is

• A. $3$
• B. $4$
• C. $1$
• D. $2$

Answer 1

Answer: (A)

$Mn{O}_4^{-}\to Mn{O}_2$
Oxidation number of
$Mn{O}_4^{-}:x-8=-1\Rightarrow x=+7$
Oxidation number of
$Mn{O}_2:x-4=0\Rightarrow x=+4$
Change in oxidation number $=3$