1.9.1 Oxidation & Reduction

Definition of Oxidation and Reduction

• Oxidation is the process of electron loss, and the substance that loses electrons is said to be oxidized.
• Reduction is the process of electron gain, and the substance that gains electrons is said to be reduced.

Oxidizing and Reducing Agents

• Oxidizing agents are substances that accept electrons from other substances, causing the other substance to lose electrons (oxidation). The oxidizing agent itself gets reduced.
• Reducing agents are substances that donate electrons, causing the other substance to gain electrons (reduction). The reducing agent itself gets oxidized.

Change in Oxidation State

The change in the oxidation state of an element helps determine whether oxidation or reduction has occurred.

• Oxidation is associated with an increase in oxidation state.
• Reduction is associated with a decrease in oxidation state.

Mnemonic: OIL RIG

A useful way to remember these concepts is:

OIL RIG: Oxidation Is Loss, Reduction Is Gain (of electrons).