Acyl chloride reaction with water. Acyl chlorides (also called acid chlorides) react vigorously with water. The reaction forms the corresponding carboxylic acid, together with fumes (white) of hydrochloric acid, formed as hydrogen chloride (HCl) reacts with water in the air. This is an addition-elimination reaction that sees a hydroxide (OH) group added to the acyl chloride from a water molecule, and a hydrogen chloride (HCl) molecule being eliminated.