Which of the following is a sulphide ore?

Argentite 2 Ag S → Cuprite 2 Cu O → Azurite 3 3 2 2 Cu CO OH → Cerussite 3 PbCO → 68. Native silver metal forms a water-soluble complex with a dilute aqueous solution of NaCN in the presence of (a) nitrogen (b) oxygen (c) carbon dioxide (d) argon The silver will dissociate in the solution of sodium cyanide in the presence of oxygen or air to form sodium argentocyanide. The reaction is given below: 2 2 2 4Ag+8NaCN+2H O+O 4Na[Ag(CN) ]+4NaOH →