CuSO₄ + H₂S → CuS + H₂O + SO₂
In this reaction, copper sulphate (CuSO₄) reacts with hydrogen sulphide (H₂S) to form copper sulphide (CuS), water (H₂O), and sulphur dioxide (SO₂). Copper sulphide is a black precipitate, while sulphur dioxide is a colourless gas with a pungent odour.
