The mechanism of acid-catalyzed hydrolysis of esters is the reverse of Fischer esterification.
Acid is only required in catalytic amounts, as in Fischer esterification, and an excess of water drives the equilibrium towards carboxylic acid and alcohol.
A base such as sodium hydroxide is required in stochiometric amounts.
Unlike acid-catalyzed ester hydrolysis, it is not an equilibrium reaction and proceeds to completion.
[2] In this example of alkaline hydrolysis of ethyl propionate, the asterisk indicates an oxygen-18 atom in an isotope labeling experiment to investigate the mechanism:[3]