When a metal is added to a solution of a compound of a less reactive metal, a displacement reaction may occur. In this type of reaction, the more reactive metal replaces the less reactive metal in the compound.

For example, if a piece of iron is added to a solution of copper sulfate, the iron will react with the copper sulfate to form iron sulfate and copper metal. This is because iron is more reactive than copper, so it is able to replace copper in the compound.

Displacement reactions can also occur between two metals in their elemental form. For example, if a piece of zinc is added to a solution of copper sulfate, the zinc will react with the copper sulfate to form zinc sulfate and copper metal. This is because zinc is more reactive than copper, so it is able to replace copper in the compound.

Displacement reactions are important in a number of industrial processes. For example, they are used to extract metals from their ores and to refine metals.