To show that iron is more reactive than copper.
Fe + CuSO4(aq) → FeSO4(aq) + Cu(s)
The type of reaction is a displacement reaction. In this process, the highly reactive metal iron replaces the copper in copper sulphate by giving up two electrons, becoming oxidised, and producing a new molecule called ferrous sulphate.
A displacement reaction occurs when an atom or a group of atoms in a molecule is displaced by another atom. A single displacement reaction occurs when an element replaces another element in a compound. Metal can only replace another metal, and a nonmetal can only substitute for another. The other element can only be replaced by a more reactive element in the compound with which it interacts.
For example, when iron is added to a copper sulphate solution, it displaces the copper metal.
A + B-C → A-C + B (General Representation of a displacement Reaction)
The above equation exists when A is more reactive than B. A and B must be either:
Metals' chemical reactivity relates to their respective places in the activity series. Certain metals can displace certain metals from their salts' aqueous solutions. Metal in a higher position in the activity series can displace a metal in a lower position from its aqueous salt solution. Metals are not the only ones affected by the displacement reaction. Nonmetals can also participate in these reactions. The halogen activity sequence is F > Cl > Br > I.