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pyrogallic acid(–ĭk), C6H6O3, white, crystalline, aromatic compound with a biting taste; it is poisonous. It melts at 133°C; and boils at 309°C;. In alkaline solution it is an active reducing agent. Pyrogallol is widely used in photographic developing and in the manufacture of some dyes. Chemically it is a phenol; its IUPAC name is 1,2,3-trihydroxybenzene.
(1,2,3-trihydroxybenzene), a trihydric phenol; a colorless, odorless crystalline solid. Melting point, 133°–134°C; boiling point, 309°C. It darkens rapidly upon exposure to air, sublimes readily, and is soluble in water, alcohol, and ether.
Pyrogallol is produced commercially by dry distillation (decarboxylation) of gallic acid and tannins (derivatives of gallic
acid). The rapid and quantitative absorption of oxygen by pyro-gallol is used in analytical chemistry, including gas analysis, and in laboratory practice. Pyrogallol is also used as a photographic developer. It is a source material in the synthesis of certain dyes.