The chemical reaction in which an acid combines with a base is called a neutralization reaction. This type of reaction results in the formation of a salt and water. For example, when hydrochloric acid (HCl), an acid, reacts with sodium hydroxide (NaOH), a base, the products are sodium chloride (NaCl), a salt, and water (H2O). The overall chemical equation for this reaction is:

HCl + NaOH → NaCl + H2O

Neutralization reactions are important in many everyday applications, such as in the production of antacids, which help to neutralize stomach acid, and in the treatment of water to remove impurities.