Ionic equation

A complete ionic equation shows those dissolved ions individually. Ions that appear unchanged on both sides are spectator ions; cancelling them produces the ionic equation for the actual chemical change.

An ionic equation focuses on the chemical change by leaving out the unchanged spectator ions. It must conserve every type of atom and also conserve electrical charge. It may contain ions alongside solids, liquids, gases or molecules; it is not necessarily an equation made entirely from ions.

An ionic equation leaves out these unchanged spectator ions so that the change is easier to see. It must still obey conservation of atoms and charge.

Leaving them out reveals the reacting ions: H⁺ and OH⁻. That is why the same ionic equation describes the water-forming step in aqueous neutralisation reactions involving different acids and alkalis.