Formic acid, molecular model. Formic acid, also called methanoic acid, is the simplest of the carboxylic acids. It is found naturally in the venom of ant and bee stings. It is used in cleaning products, in the production of leather and rubber, and as a preservative and antibacterial agent in livestock feed. Atoms are represented as spheres and are colour-coded; carbon (grey), hydrogen (white) and oxygen (red).