Question

The oxidation number of sulphur in $H_{2}S_{2}O_{8}$ is

• A. $+2$
• B. $+4$
• C. $+6$
• D. $+7$

Answer 1

Answer: (C)

$\because 2 O$ -atoms are in peroxide linkage
$\therefore $ Their oxidation state $=-1$
and, oxidation state of remaining $6O$ -atoms $=-2$
Oxidation state of $H$ -atoms $=+1$
Let oxidation state of $S$ atom $=x$
$S _{2} H _{2} O _{6} O _{2}$
$\therefore 2 x+2(+1)+6(-2)+2(-1) =0$
$2 x+2-12-2 =0$
$x =+6$