Acids
in chemistry, a salt of hydrogen in which the hydrogen can be replaced by a metal, or can, with a basic metallic oxide, form a salt of that metal and water. Acid oxides of the same element are distinguished by the termination of -ous and -ic-as sulphurous and sulphuric-the latter containing the most oxygen; they are also called anhydrides.
They unite with water and form acids having the same terminations. By replacement of the hydrogen by a metal they form salts distinguished by the terminations -ite and -ate respectively. These acids are called oxygen acids. Many acids are formed by direct union of hydrogen with an element, as hydrochloric acid (HCl), hydrosulphuric acid (H2S), or with an organic radical, as hydrocyanic acid, H(CN). Acids which are soluble in water redden blue litmus, and have a sour taste. Organic acids can be produced by the oxidation of an alcohol or aldehyde. They contain the monad ACLAND radical (HOOC), once if they are monobasic, twice if dibasic, etc. They are also classed as monatomic, diatomic, etc., according as they are derived from a monatomic or diatomic alcohol, etc. Many organic acids occur in the juices of vegetables, some in animals, as formic acid in ants.