Question

The oxidation numbers of the sulphur atoms in peroxomonosulphuric acid $\left(H_{2}S{O}_5\right)$ and peroxodisulphuric acid $\left(H_2{S}_2{O}_8\right)$ are respectively

• A. $+8$ and $+7$
• B. $+3$ and $+3$
• C. $+6$ and $+6$
• D. $+4$ and $+6$

Answer 1

The correct option is C $+6$ and $+6$

Both the peroxomonosulphuric acid $\left(H_{2}S{O}_5\right)$ and peroxodisulphuric acid $\left(H_2{S}_2{O}_8\right)$ have peroxide linkage and have the following structures.

Thus, the oxidation number of $S$ in $H_{2}S{O}_5$ is calculated as:

$\underset{\left(forH\right)}{2\times (+1)}+\underset{\left(forS\right)}{X}+\underset{forO}{3\times (-2)}+\underset{\left(forperoxide\right)}{2\times (-1)}=0$

$2+x-6-2=0$

$\therefore x=+6$

Thus, oxidation number of $S$ in $H_2{S}_2{O}_8$ is calculated as

$\underset{\left(forH\right)}{2\times (+1)}+\underset{\left(forS\right)}{2\times \left(x\right)}+\underset{\left(forO\right)}{6\times (-2)}+\underset{\left(forperoxide\right)}{2\times (-1)}=0$

$2+2x-12+2=0$

$\therefore x=+6$.