Oxalic acid Oxalic acid Oxalic acid is an organic compound with the formula CHO. It is a colorless crystalline solid that forms a colorless solution in water. Its condensed formula is HOOCCOOH, reflecting its classification as the simplest dicarboxylic acid. Its acid strength is much greater than that of acetic acid. Oxalic acid is a reducing agent and its conjugate base, known as oxalate (), is a chelating agent for metal cations. Typically, oxalic acid occurs as the dihydrate with the formula CHO·2HO. It occurs naturally in many foods, but excessive ingestion of oxalic acid or prolonged skin contact can be dangerous.
Terephthalic acid Terephthalic acid Terephthalic acid is an organic compound with formula CH(COH). This white solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. Several million tonnes are produced annually. The common name is derived from the turpentine-producing tree "Pistacia terebinthus" and phthalic acid. Terephthalic acid was first isolated (from turpentine) by the French chemist Amédée Cailliot (1805–1884) in 1846. Terephthalic acid became industrially important after World War II. Terephthalic acid was produced by oxidation of "p"-xylene with dilute nitric acid. Air oxidation of "p"-xylene gives "p"-toluic acid, which resists