Half-equations

What is half-equations?

A half-equation shows just the oxidation or just the reduction step of a redox reaction, including the electrons transferred. Example: Zn → Zn²⁺ + 2e⁻ (oxidation half). Half-equations must balance for both atoms and charge. Combining the two half-equations (so electrons cancel) gives the overall ionic equation. Used heavily in A-Level electrochemistry, electrolysis and redox titrations.