In a laboratory, acids are used as reagents or catalysts in many types of chemical reactions.
Acids are substances that have a sour taste, a low pH (<7), and turn litmus paper red. They also react with bases (yielding water and ionic compounds called salts) and release hydrogen gas. Chemically, an acid is a molecule or ion that acts as a proton (Brønsted-Lowry acid) in a non-aqueous solution. Acids form hydronium ions (H3O+) when reacted with water.
An acid is alternatively defined as a molecule or ion that accepts an electron pair (Lewis acid). One example is trifluoroborane, which has a boron atom capable of accepting an electron pair from ammonia (NH3) to form NH3-BF3.
Common inorganic acids include hydrochloric, sulfuric, nitric, and phosphoric acids. Common organic acids include acetic, benzoic, citric, and lactic acids.
- Strong acids, such as sulfuric and hydrochloric acid, are highly corrosive and have extensive commercial applications
- H2SO4 is used to process petroleum and minerals, and to make other chemicals like nitric acid
- HCl is used to pickle steel and other metals
- Some acids are used as neutralizers to produce salts; for example, ammonium nitrate is produced by the reaction of nitric acid with ammonia
- Many acids are also used in the food and beverage industry
Various grades of acids are available in concentrated form or in solutions based on purity, including reagent (ACS), laboratory, and other technical and specialty preparations.