CBSE Class 12-science Answered

An oxidizing agent, or oxidant, gains electrons and is reduced in a chemical reaction. Also known as the electron acceptor, the oxidizing agent is normally in one of its higher possible oxidation states because it will gain electrons and be reduced.

A reducing agent, or reductant, loses electrons and is oxidized in a chemical reaction. A reducing agent typically is in one of its lower possible oxidation states and is known as the electron donor. A reducing agent is oxidized because it loses electrons in the redox reaction.

For example: Consider following reaction,

Cl_2(aq) + 2Br⁻ _(aq) → 2Cl⁻ _(aq) + Br_{2 (aq)}

Oxidation half reaction: 2Br⁻ _(aq) → Br_{2 (aq)}

Reduction half reaction: Cl_{2 (aq)} → 2Cl⁻ _(aq)

Br⁻ loses an electron; it is being oxidized from Br⁻ to Br₂, thus Br⁻ is the reducing agent.

Cl₂ gains one electron; it is being reduced from Cl₂ to 2 Cl⁻, thus Cl₂ is the oxidizing agent.