Answer :
\( Na_{2}SO_{4}{(aq)}+BaCl_{2}{(aq)} \rightarrow BaSO_{4}{(s)}+2NaCl(aq) \) The above reaction is an example of double displacement reaction. In the above reaction when sodium sulphate reacts barium chloride It form a white colour precipitate known as Barium sulphate along with it sodium chloride this Barium sulphate is formed by the reaction of \(SO_{4}^{2-} \) and \(Ba^{2-} \) in this reaction these ions of reactant molecule exchange with each other to form product so this reaction is called as double displacement reaction.