Question

What is the difference between displacement and double displacement reactions? Write equations for these reactions.

Answer 1

Displacement reaction: A displacement reaction is a type of chemical reaction in which a more reactive element displaces a less reactive element from its compound or salt solution.
Example: When Zinc$\left(Zn\right)$ metal is dipped in the Copper sulphate$\left(CuS{O}_4\right)$ solution, Zinc displaces the copper metal from its salt solution and forms Zinc sulphate$\left(ZnS{O}_4\right)$ and Copper is deposited at the bottom.

${\text{CuSO}}_4\text{(aq)}+\text{Zn(s)}\to {\text{ZnSO}}_4\text{(aq)}+\text{Cu(s)}$

Double displacement reaction: A double displacement reaction is a type of chemical reaction in which 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.
Example: When Sodium sulpahte$\left(N{a}_{2}S{O}_4\right)$ is treated with Barium chloride$\left(BaC{l}_2\right)$, it will lead to the formation of Barium sulphate$\left(BaS{O}_4\right)$ and Sodium chloride$\left(NaCl\right)$.

${\text{Na}}_2{\text{SO}}_4\text{(aq)}+{\text{BaCl}}_2\text{(aq)}\to {\text{BaSO}}_4\text{(s)}+2\text{NaCl(aq})$