Question

some articles made of silver,copper and iron get coloured coating over them when they are exposed to air . Identify the colour and chemical name of the substance of coqting in each case .

Answer 1

silver-Ag2S(black)
iron-rust(brown)
copper-copper carbonate-CuCO3.Cu(OH)2(green)

Answer 2

Silver Coating    - Black  - Ag₂S - Silver Sulphide
Copper Coating - Green - CuO  - Copper Chloride
Iron Coating       - Brown - Fe₂O₃ - Ferric Oxide

:) Hope this Helps !!!