Question

When hydrogen sulfide gas is passed through a blue solution of copper sulfate, a black precipitate of copper sulfide is obtained and the sulphuric acid so formed remains in the solution. The reaction is an example of:

• A. a combination reaction
• B. a displacement reaction
• C. a decomposition reaction
• D. a double decomposition reaction

Answer 1

The correct option is D a double decomposition reaction

$CuS{O}_4+H_{2}S⟶C{u}_{2}S+H_{2}S{O}_4$

This is known as a double displacement reaction or metathesis.

Hence, option D is correct.