Carboxylic acids contain the carboxyl (-COOH) functional group. Their general formula is R-COOH. Vinegar which is also called acetic acid has the formula CH3COOH.
It is obtained by the oxidation of ethanol in the presence of conc. H2SO4 and K2Cr2O7.
CH3CH2OH + 2[O] → CH3COOH + H2O
It is soluble in water as it forms hydrogen bond with water molecule. It is used as preservative.
Lactic acid is present in sour milk, also produced in muscles during heavy exercise. Citric acid present in citrus fruits and ascorbic acid present in Vitamin C are carboxylic acids.