1
$\begingroup$

I am currently in high school and have encountered the following reaction in my course on electrochemistry:

$$\ce{2 SO4- -> S2O8^2- + 2 e-}$$

Why this reaction happens in the first place? Isn’t the maximum oxidation state of sulfur only +6?

$\endgroup$
1

1 Answer 1

6
$\begingroup$

The oxidation number of sulfur in peroxydisulfate is still +6.

But the oxidation number of oxygen in peroxy group $\ce{\bond{-}O-O\bond{-}}$ is not −2, but −1.

$$\ce{O^{-}-SO2-O-O-SO2-O^{-}}$$

The reaction $\ce{2 SO4^2- -> S2O8^2- + 2 e-}$ does not oxidize sulfur. It oxidized two oxygen atoms and joins them to the peroxy group.

$\endgroup$
0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.