Benzoic acid is a colorless, odorless, flaky crystal.Melting point 122.13℃, boiling point 249℃, relative density 1.2659 (15/4℃).Rapid sublimation at 100℃, its steam has a strong irritation, inhalation after easy to cause cough.Slightly soluble in water, easily soluble in ethanol, ethyl ether and other organic solvents.Benzoic acid is a weak acid, stronger than fatty acids.Their chemical properties are similar, can form salt, ester, acyl halide, amide, acid anhydride, etc., are not easy to be oxidized.Electrophilic substitution reaction can occur on the benzene ring of benzoic acid, and the interposition substitution production is mainly obtained.