MgCl2+2NaCl=Mg(OH)2↓+2NaCl
AlCl3+NaOH:
刚滴入时:AlCl3+ 3NaOH = Al(OH)3 + 3NaCl 有沉淀生成
过量以后:Al(OH)3 + NaOH = NaAlO2 + 2H2O 沉淀溶解