Salt, Chemical, is a compound that results when a base neutralizes an acid. In this reaction, the metal in the base displaces the hydrogen in the acid. For example, ordinary table salt, sodium chloride (NaCl), is formed when the base sodium hydroxide (NaOH) neutralizes hydrochloric acid (HCl). The salt calcium carbonate is formed when the base calcium hydroxide neutralizes carbonic acid. See Neutralization.