If you collect silver coins and copper coins you may have seen that after some days a black coating forms on silver coins and a green coating on copper coins. Which chemical phenomenon is responsible for these coatings? Write the chemical name of the black and green coatings.
Corrosion is responsible for the formation of this coating. Black coating is due to formation of Ag2S and green coating is due to formation of CuCO3.Cu(OH)2.