Concept preview

What you will be able to do

1. 01Split a redox reaction into half-reactions
2. 02Balance a half-reaction for atoms and charge
3. 03Combine half-reactions so the electrons cancel

Simple equations can be balanced by inspection, but many redox equations — especially those in acidic or basic solution involving polyatomic ions — are far too complex for trial and error. The reliable tool is the half-reaction method (also called the ion-electron method), which breaks the problem into two smaller, manageable pieces and guarantees that both mass and charge are conserved.