Choose the correct option from given alternative:
When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of copper sulphide is obtained and the sulphuric acid so formed remains in the solution. The reaction is an example of a:
Options
Combination reaction
Displacement reaction
Decomposition reaction
Double displacement reaction
Solution
In the case of a double displacement reaction, two reactants exchange their ions and form new products.
\[\ce{\underset{\text{Hydrogen sulphide}}{H2S(g)}+\underset{\text{Copper sulphate}}{CuSO4(aq)}->\underset{\text{Copper sulphide,black ppt}}{CuS(s)}+\underset{\text{Sulphuric acid}}{H2SO4(aq)}}\]
This reaction is an example of a double displacement reaction.
Hence, the correct answer is Double displacement reaction.
