Question

Identify the type of chemical reaction taking place in each of the following:
Barium chloride solution is mixed with copper(II) sulphate solution and a white precipitate is observed.

Answer 1

1. Type of reaction

Combination reaction: Reaction in which two or more reactants combine to form a single product. $\mathrm{A}+\mathrm{B}\to \mathrm{C}$

Decomposition reaction: Reaction in which reactant is broken down into two or more products in the presence of heat, light or electricity. $\mathrm{A}\to \mathrm{B}+\mathrm{C}$

Displacement reaction: Reaction in which one of the higher reactive element displaces a less reactive element from its solution. $\mathrm{A}+\mathrm{BC}\to \mathrm{AC}+\mathrm{B}$ ( Here A is more reactive than B)

Double displacement reaction: Reaction in which ions of both the reactants interchange their place and form new compounds. $\mathrm{AB}+\mathrm{CD}\to \mathrm{AD}+\mathrm{CB}$

2. Reaction:

$\mathrm{BaCl}{}_2(\mathrm{aq})+\mathrm{CuSO}{}_4(\mathrm{aq})\to \mathrm{BaSO}{}_4(\mathrm{s})+\mathrm{CuCl}{}_2(\mathrm{aq})$
Barium chloride Copper sulphate Barium sulphate Copper chloride

Here $\mathrm{Ba}$ and $\mathrm{Cu}$ are interchanging their place and forming new compounds so it is a double displacement reaction.

Also in this reaction white precipitates of $\mathrm{BaSO}{}_4$are formed which are insoluble in water so it is also known as a precipitation reaction.