(1)NaOH+HCL==NaCl+H 2O
(2)Ca(OH) 2+H 2SO 4==CaSO 4+2H 2O
(3)NH 3·H 2O+HCl==NH 4Cl+H 2O
(4)Cu(OH) 2+H 2SO 4==CuSO 4+2H 2O