In peroxodisulphuric acid, H2S2O8, the oxidation state of sulphur and the number of S=O bonds are respectively

JEE Main levelSingle correct optionDifficulty 2 of 3pn207

In peroxodisulphuric acid, $H X_{2} S X_{2} O X_{8}$ , the oxidation state of sulphur and the number of S=O bonds are respectively

The structure is

HO X_{3} S - O - O - SO X_{3} H

with a peroxo link:

2 (+ 1) + 2 x + 6 (- 2) + 2 (- 1) = 0

gives

x = + 6

. Each S carries two S=O bonds, so there are 4 in all. Ignoring the peroxo link would wrongly give

+ 7