Question

The roasted sulphide ore of Cu contains ______.

Options

• Cu₂O only

• Cu₂S only

• both Cu₂O and Cu₂S

• metallic copper

Answer 1

The roasted sulphide ore of Cu contains both Cu₂O and Cu₂S.

Explanation:

When copper pyrites (CuFeS₂) is roasted in air, part of the sulphide is oxidised to Cu₂O, and the rest remains as Cu₂S.
During the subsequent Bessemerisation process, these two compounds react together to form metallic copper.

\[\ce{2Cu2S + 3O2 -> 2Cu2O + 2SO2}\]

\[\ce{Cu2S + 2Cu2O -> 6Cu + SO2 \uparrow}\]

Hence, the roasted ore contains both Cu₂O and Cu₂S.