CBSE Class 10 Science 2018 · Paper 31(B) · Question 16

Difference: in a displacement reaction, a more reactive element displaces a less reactive element from its compound in solution, so an element and a compound react to give a new element and a new compound. In a double displacement reaction, two compounds react by exchanging their ions to form two new compounds; one of the products is often an insoluble precipitate. Displacement reactions: (i) $\text{Fe(s)}+{\text{CuSO}}_4\text{(aq)}\to {\text{FeSO}}_4\text{(aq)}+\text{Cu(s)}$ (ii) $\text{Zn(s)}+{\text{FeSO}}_4\text{(aq)}\to {\text{ZnSO}}_4\text{(aq)}+\text{Fe(s)}$ Double displacement reactions: (i) ${\text{AgNO}}_3\text{(aq)}+\text{NaCl(aq)}\to \text{AgCl(s)}+{\text{NaNO}}_3\text{(aq)}$ (ii) ${\text{Na}}_2{\text{SO}}_4\text{(aq)}+{\text{BaCl}}_2\text{(aq)}\to {\text{BaSO}}_4\text{(s)}+2\text{NaCl(aq)}$ Other correct examples also earn credit.