Neutralization occurs when a base is reacted with an acid. The OH ions in the base react with the H ions in the acid to form HO, water. In this reaction, the base is protonated and the acid is (deprotonation|deprotonated). To neutralise a substance (e.g alkali substance), you must put an equal amount of an acid into the alkali in order for it to become neutral(also known as pH 7). Titration uses neutralization to measure chemical concentrations.