In a displacement reaction, a more reactive element displaces a less reactive element from its compound or salt solution.
For example: CuSO4(aq)+Zn(s)→ZnSO4(aq)+Cu(s)
[1 Mark]
In a double displacement reaction, two compounds react by exchanging their ions to form new compounds. It is typically identified by the formation of a product that is a precipitate.
For example: Na2SO4(aq)+BaCl2(aq)→BaSO4(s)+2NaCl(aq)
[1 Mark]