Question

What will be the oxidation state of sulphur in $SO_4^{2-}$?

• A. +4
• B. +6
• C. +7
• D. +5

Answer 1

Answer: (B)

+6

Answer 2

In the sulfate ion $SO_4^{2-}$, let the oxidation state of S be $x$. Oxygen has an oxidation state of $-2$. The sum of oxidation states equals the charge on the ion:

$$x + 4(-2) = -2 \implies x - 8 = -2 \implies x = +6.$$

Therefore, the oxidation state of sulphur in $SO_4^{2-}$ is +6.