benzoic acid (bĕnzōˈĭk) [key], C6H5CO2H, crystalline solid organic acid that melts at 122°C and boils at 249°C. It is the simplest aromatic carboxylic acid (see aryl group and carboxyl group). In addition to being synthesized from a variety of organic compounds (e.g., benzyl alcohol, benzaldehyde, toluene, and phthalic acid), it may be obtained from resins, notably gum benzoin. It is used largely for making its salts and esters, most notably sodium benzoate, which is widely used as a preservative in foods and beverages and as a mild antiseptic in mouthwashes and toothpastes.
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