Question

Find oxidation number of Magnese in $K_{2}Mn{O}_4$.

Answer 1

$K_2{MnO}_4⟶{2K}^{+}{\left[{MnO}_4\right]}^{2-}$

Let the oxidation state of $Mn$ in ${MnO}_4^{2-}$ be $x$

The oxidation state of $O$ is -2

$\therefore$ For ${MnO}_4^{2-}:-x+4(-2)=-2$

$\therefore x-8=-2$

$\therefore x=+6$

Therefore the oxidation state of $Mn$ is +6.