Question

If copper is kept exposed to damp air for a considerable time, it gets a green coating on its surface. This is due to the formation of:
(a) hydrated copper sulphate
(b) copper oxide
(c) basic copper carbonate
(d) copper nitrate

Answer 1

(c) basic copper carbonate
Copper reacts slowly with water and carbon dioxide in the atmosphere to form copper carbonate. This gives a green colour coating to its surface.