Oxidation is the opposite of reduction. A reduction-reaction always comes together with an oxidation-reaction. Oxidation and reduction together are called redox (reduction and oxidation). Oxygen does not have to be present in a reaction, for it to be a redox-reaction.
In terms of oxygen transfer[change | change source]
Oxidation is a gain of oxygen. Reduction is a loss of oxygen. For example:
- Fe2O3 + 3CO ---> 2Fe + 3CO2
Both reduction and oxidation go on at the same time which is a redox-reaction. The loss of Hydrogen-atoms; and, the simultaneously gaining of oxygen-atoms, is known as oxidation.