Metallic oxides of zinc, magnesium and copper were heated with iron metal. In which cases will you find displacement reactions taking place? Write the balanced chemical equations for each reaction.

Dear Student,
Reactivity series of metals come in the order Cu<Fe<Zn<Mg. So according to this, if metallic oxides of zinc, magnesium and copper were heated with iron metal, then iron metal can displace copper but not zinc and magnesium. The chemical reaction  between copper and iron metal is
CuO +Fe $--->$FeO + Cu  
Regards