Base
Base, a chemical compound that is capable of accepting hydrogen ions from another substance. (An ion is an electrically charged atom or radical—a group of atoms that acts as a single atom.) Bases will neutralize acids by combining with the hydrogen of the acid. A salt is always formed by the reaction of an acid with a base.
Most bases are solids at ordinary temperatures. Many, however, are liquids and a few are gases. When dissolved in water, bases typically have a bitter taste, feel soapy, will turn red litmus blue, and can conduct an electric current. Many bases are highly flammable. Some, such as sodium hydroxide, can cause severe chemical burns on the skin.
Bases are classified as either inorganic or organic. Some inorganic bases (such as magnesium hydroxide) occur in nature as minerals. Most, however, are manufactured from mineral substances. Organic bases occur in, or can be produced from, animal or plant matter.
Most common inorganic bases are hydroxides—compounds that contain the hydroxyl radical (OH-). Other inorganic bases include ammonia and many metal oxides; some salts (such as potassium carbonate) function as bases in solution and therefore are also considered bases. In chemistry, the term alkali is often used for inorganic bases that can either release or form hydroxyl radicals in water solution. The term is applied to the hydroxides and carbonates of ammonia and of the alkali metals and to the oxides and hydroxides of the alkaline-earth metals.
Common inorganic bases are sodium hydroxide (caustic soda), potassium hydroxide (caustic potash), calcium oxide (quicklime), and sodium carbonate (soda ash). Inorganic bases are used in making soap, glass, paper, chemicals, plastics, dyes, and many other substances.
Organic bases always contain carbon, hydrogen, and nitrogen. Alkaloids and most amines are organic bases. Alkaloids are found in certain plants, and are used chiefly as drugs. Amines usually occur in nature in decaying plant and animal matter. Commercial amines, which can be derived from ammonia, are used mainly as solvents and in the manufacture of rubber, soap, detergents, dyes, chemicals, vitamins, insecticides, and fungicides.