Hydrolysis of O, O-Diethyl, O-P -Cyan Phenyl Phosphate (Organophosphorus Compound) Has Been Studied In Acidic Medium With Catalyst Cu++ Cation and the Rate Maxima Observed Were at Around Ph 6.0. Since the Metal Aquo Complexes Are Known to Exist In Equilibrium With Deprotonated Species and Therefore, Metal Bound Oh- Nucleophile Might Be Available Abundantly Even In Acidic Aqueous Solutions.