Acid chlorides are useful for the preparation of amides, esters, anhydrides.  These reactions generate chloride, which can be undesirable. Acyl chlorides hydrolyze, yielding the carboxylic acid:
This hydrolysis is usually a nuisance rather than intentional. Acyl chlorides are used to prepare acid anhydrides, amides and esters, by reacting acid chlorides with: a salt of a carboxylic acid, an amine, or an alcohol, respectively.