A:氯化铁溶液中加入铜粉:Fe3+Cu=Fe2++Cu2+
B:将含等物质的量的NaHCO3和Ba(OH)2溶液混合:HCO3-+Ba2++OH-=BaCO3↓+H2O
C:少量SO2通入次氯酸钙溶液中:Ca2++2ClO-+SO2+H2O=CaSO3↓+2HClO
D:少量AlCl3溶液滴入过量氨水中:Al3++4NH3·H2O=AlO2-+4NH4++2H2O
Mr father this watch in 2006. He it for 10 years.