(organic chemistry) an unsaturated organic dicarboxylic acid, HOOCCH=CHCOOH, the geometric isomer of maleic acid from which it may be prepared by heating; it is found in many plants, including fungi and mosses, and is essential in the chemistry of respiration; it has a number of industrial applications, and its esters, the fumarates, are used in the treatment of psoriasis

(organic chemistry) An unsaturated organic acid, trans-CH₃-CH=CH-COOH, found in croton oil and having many industrial uses; the cis- form is isocrotonic acid.

(chemistry) a dicarboxylic acid, HOOC(CH₂)₃COOH, formed during the catabolism of tryptophan

(organic chemistry) A colourless, crystalline dicarboxylic acid, (COOH)₂, found in rhubarb, spinach and other plants, often as crystals of the calcium salt.

(chemistry) a solid white acid, H₂SeO₄, having the same structure and similar reactions as sulphuric acid

(organic chemistry) an equal mixture of the d- and l- forms of tartaric acid found in grape juice; the isomers can be separated via crystallization

(biochemistry) The aldaric acid, 2,3 dihydroxy-succinic acid, that occurs naturally in many plants, in wine and in tamarind; it is used as the salts cream of tartar and Rochelle salt.

(organic chemistry) A colourless liquid unsaturated organic acid, CH₂=CHCOOH; used as a monomer in the production of acrylic resins; forms acrylate esters by combination with alcohols.

A weak unstable acid, H₂CO₃, known only in solution, and as carbonate salts; it is present in carbonated drinks, and sparkling wine, but decomposes to form carbon dioxide and water.

(chemistry) a solution of hydrogen iodide, HI, in water; it is a strong acid and reducing agent