Question

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> What happens when copper sulphide is treated with dilute hydrochloric acid?

Answer 1

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> The black coloured copper sulphide turns blue and hydrogen sulphide gas is liberated. The reaction involved is:
$CuS+2HCl\to CuC{l}_2+H_{2}S$