Half-reaction

Definition

A half-reaction is either the oxidation or reduction component of a redox reaction. It shows the loss or gain of electrons by a species.

5 Must Know Facts For Your Next Test

1. In a redox reaction, the oxidation half-reaction represents the loss of electrons.
2. The reduction half-reaction represents the gain of electrons in a redox reaction.
3. Half-reactions must be balanced for both mass and charge to accurately reflect the conservation laws.
4. Combining balanced oxidation and reduction half-reactions gives the overall balanced redox equation.
5. Half-reactions are useful for identifying the oxidizing and reducing agents in a chemical reaction.

Review Questions

• What does an oxidation half-reaction represent?
• How do you balance a half-reaction for both mass and charge?
• Why are half-reactions important in understanding redox reactions?

Related terms

Oxidation:

The process in which an atom, ion, or molecule loses electrons.

Reduction:

The process in which an atom, ion, or molecule gains electrons.

Redox Reaction:

A chemical reaction involving the transfer of electrons between two species; it includes both oxidation and reduction processes.