①NaCl + AgNO₃ = AgCl↓(白色)+ NaNO₃;
②KCl + AgNO₃ = AgCl↓(白色)+ KNO₃;
④MgCl₂+2AgNO₃ = 2AgCl↓(白色)+Mg(NO₃)₂;
反应的离子方程式为: