Question

The oxidation number of iodine in ${\mathrm{IO}}_4^{-}$ is .

• A. $-1$
• B. $+2$
• C. $+7$
• D. $+5$

Answer 1

The correct option is C

$+7$

The explanation for the correct option

(C) $+7$

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."

• The oxidation number of iodine in ${\mathrm{IO}}_4^{-}$ is $x$.
• The oxidation number of oxygen is $-2$.

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

The oxidation number of iodine in ${\mathrm{IO}}_4^{-}$ is $+7$.

The explanation for the incorrect option

The oxidation number of iodine in ${\mathrm{IO}}_4^{-}$ is $+7$. So, options (A), (B), and (D) are incorrect.

Hence, option (C) is the correct answer.