Acid: A compound in which all cations produced during dissociation are hydrogen ions, called acid.

Alkali: A compound in which all anions produced during dissociation are hydroxyl ions, called alkali.

Salt: The compound of acid radical ion and metal radical ion (including ammonium radical) is called salt.

Examples of related chemical formulas:

Acids: H2SO4 (sulfuric acid), HCl (hydrochloric acid), HNO3 (nitric acid)

Alkali: sodium hydroxide, potassium hydroxide

Salt: sodium carbonate, copper sulfate