acid
acid [CHEM] 1. Any of a class of chemical compounds whose aqueous solutions turn
blue litmus paper red, react with and dissolve certain metals to form salts, and react
with bases to form salts. 2. A compound capable of transferring a hydrogen ion
in solution. 3. A substance that ionizes in solution to yield the positive ion of the
solvent. 4. Amolecule or ion that combines with anothermolecule or ion by forming
a covalent bond with two electrons from the other species.