The reaction in which salts undergo complex decomposition with water to form acids and bases is called hydrolysis, and the acids and bases hydrolyzed are the acids and bases corresponding to the anions of the salt. If the original acid is a strong acid and the original base is a strong base, the salt is called a strong acid-strong base salt. Similarly:
NaCl Strong acid and strong base salt Na2S Weak acid and strong base salt NH4CL Strong acid and weak base salt In this order