Hydrochloric acid a hazardous liquid which must be used with care. When used on brickwork the reaction with the mortar only continues until the acid has all been converted, producing calcium chloride, carbon dioxide, and water: Many chemical reactions involving hydrochloric acid are applied in the production of food, food ingredients, and food additives. Typical products include aspartame, fructose, citric acid, lysine, hydrolyzed vegetable protein as food enhancer, and in gelatin production. Food-grade (extra-pure) hydrochloric acid can be applied when needed for the final product. Gastric acid is one of the main secretions of the stomach. It consists mainly of hydrochloric acid
Gentisic acid Gentisic acid Gentisic acid is a dihydroxybenzoic acid. It is a derivative of benzoic acid and a minor (1%) product of the metabolic break down of aspirin, excreted by the kidneys. It is also found in the African tree "Alchornea cordifolia" and in wine. Gentisic acid is produced by carboxylation of hydroquinone. This conversion is an example of a Kolbe–Schmitt reaction. Alternatively the compound can be synthesized from salicylic acid via Elbs persulfate oxidation. In the presence of the enzyme gentisate 1,2-dioxygenase, gentisic acid reacts with oxygen to give maleylpyruvate: As a hydroquinone, gentisic acid is readily oxidised and is