The oxidation state of oxygen in tetraoxosulphate(IV) acid is

The oxidation state of an atom in a compound is the charge it would have if all the shared electrons were assigned to the more electronegative atom. In tetraoxosulphate(IV) acid, which is also known as sulfuric acid, the formula is H2SO4. The oxidation state of hydrogen is +1 because it usually has a +1 oxidation state in compounds. To find the oxidation state of sulfur, we use the fact that the oxidation states of all the atoms in a compound add up to zero. Since there are two hydrogen atoms with a total oxidation state of +2, and four oxygen atoms with a total oxidation state of -8 (since the usual oxidation state of oxygen in a compound is -2), the oxidation state of sulfur must be +6 for the sum of the oxidation states to equal zero. Therefore, the oxidation state of oxygen in tetraoxosulphate(IV) acid is -2, since the sum of the oxidation states of all the atoms in the compound must equal zero.