Question

What is the oxidation state of S in the following compound?

SO₂

Answer 1

Let the oxidation state of sulphur (S) be x.

Oxygen (O) = –2 (standard oxidation state)

Number of oxygen atoms = 2

∴ Total oxidation state of oxygen atom = 2 × (–2) = –4

Since SO₂ is a neutral molecule, the sum of oxidation states = 0

x + 2(−2) = 0

⇒ x − 4 = 0

⇒ x = +4

∴ The oxidation state of sulphur (S) in SO₂ is +4.