Texas State Technical College describes benzoic acid as a polar aromatic carboxylic acid. Benzoic acid is composed of a large, non-polar benzene ring attached to a smaller, polar carboxyl group. The compound is considered slightly polar, because the carboxylic functional group has some polarity with the benzene ring.
Benzoic acid is a colorless crystalline solid with a chemical formula of C6H5COOH. In most cases, polar compounds are soluble in polar solvents like water, but benzoic acid is a unique exception. Because of its large, hydrophobic benzene ring, benzoic acid is only slightly soluble in water when heated. Benzoic acid can be made soluble, however, by reacting it with sodium hydroxide to produce a water-soluble salt by way of hydrolysis. Benzoates, the salt products of benzoic acids, act as food preservatives by inhibiting the growth of molds, yeasts and bacteria. Benzoic acid is relatively non-toxic and is metabolized by the liver and excreted in the urine as hippuric acid.