Gallic Acid
Gallic Acid, an organic acid composed of carbon, hydrogen, and oxygen. It occurs in nature in tea leaves and in the bark of oak and hemlock trees. The acid is prepared commercially by boiling tannin in an acidic solution or a caustic soda solution; it forms colorless crystals. Gallic acid is used in making dyes and permanent ink, and as a tanning agent for leather.
Chemical formula: C6H2(OH)3COOH.