Hydrochloric acid enzyme pepsin by self-cleavage. After leaving the stomach, the hydrochloric acid of the chyme is neutralized in the duodenum by sodium bicarbonate. The stomach itself is protected from the strong acid by the secretion of a thick mucus layer, and by secretin induced buffering with sodium bicarbonate. Heartburn or peptic ulcers can develop when these mechanisms fail. Drugs of the antihistaminic and proton pump inhibitor classes can inhibit the production of acid in the stomach, and antacids are used to neutralize excessive existing acid. Concentrated hydrochloric acid (fuming hydrochloric acid) forms acidic mists. Both the mist and the solution have
Gallic acid Gallic acid Gallic acid (also known as 3,4,5-trihydroxybenzoic acid) is a trihydroxybenzoic acid, a type of phenolic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. The chemical formula of gallic acid is CH(OH)COOH. It is found both free and as part of hydrolyzable tannins. The gallic acid groups are usually bonded to form dimers such as ellagic acid. Hydrolyzable tannins break down on hydrolysis to give gallic acid and glucose or ellagic acid and glucose, known as gallotannins and ellagitannins, respectively. Gallic acid forms intermolecular esters (depsides) such as digallic and trigallic acids, and