oxidation

In chemistry, the loss of electrons, gain of oxygen, or loss of hydrogen by an atom, ion, or molecule during a chemical reaction.

At a simple level, oxidation may be regarded as the reaction of a substance with oxygen. For example, rusting, respiration, and combustion (burning) are all oxidation reactions. When carbon is burned in air it is oxidized to carbon dioxide:

C + O₂ → CO₂

Oxidation may be brought about by reaction with another compound (oxidizing agent), which simultaneously undergoes reduction, or electrically at the anode (positive electrode) of an electrolytic cell.