Question

What is the oxidation number of manganese $\left(\mathrm{Mn}\right)$ in potassium permanganate$\left({\mathrm{KMnO}}_4\right)$?

• A. $+5$
• B. $+7$
• C. $+8$
• D. $+9$

Answer 1

The correct option is B

$+7$

Explanation:

Oxidation number: Oxidation number denotes the oxidation state of an element in a compound ascertained according to a set of rules formulated on the basis that electron pair in a covalent bond belongs entirely to a more electronegative element.

Calculating the oxidation number of Manganese(Mn) in ${\mathrm{KMnO}}_4$:

The oxidation state of Potassium(K) = +1

The oxidation state of Oxygen(O) = -2

Consider the oxidation state of Manganese(Mn) = x

Now,

$$\begin{gathered} +1+\mathrm{x}+\left(-2\times 4\right)=0 \\ +1+\mathrm{x}-8=0 \\ \mathrm{x}=+7 \end{gathered}$$

So, the oxidation number of manganese $\left(\mathrm{Mn}\right)$ in potassium permanganate$\left({\mathrm{KMnO}}_4\right)$ is $+7$.

Hence, option (B) is correct.