When a metal reacts with a compound of a different metal, the more reactive metal displaces the less reactive metal from its compound.The reaction is a redox reaction.Mg(s) + CuSO4(aq) → MgSO4(aq) + Cu(s)In this reaction magnesium, a silvery-grey solid, reacts with a blue solution of copper sulfate to give a colourless solution of magnesium sulfate and a red-brown solid of copper metal.