What is the oxidation state of sulfur in the sulfate ion, SO_4^{2-}?

• A. +2
• B. -2
• C. +6
• D. +4

Answer: (C)

Verified step by step guidance

1. Identify the overall charge of the sulfate ion, which is \(-2\) for \(\mathrm{SO_4^{2-}}\).
2. Recall that oxygen almost always has an oxidation state of \(-2\) in compounds (except in peroxides or when bonded to fluorine).
3. Since there are 4 oxygen atoms, calculate the total oxidation contribution from oxygen: \$4 \times (-2) = -8$.
4. Let the oxidation state of sulfur be \(x\). Write the equation for the sum of oxidation states equal to the overall charge: \(x + (-8) = -2\).
5. Solve for \(x\) to find the oxidation state of sulfur: \(x = -2 + 8\).