Question

write the chemical name of the coating that forms on silver and and copper articles when these are left exposed to moist air?

Answer 1

Sliver -Pb and otherwise is cu-cooper

Answer 2

Silver reacts with moist hydrogen sulphide present in air and forms a coating on it of silver sulphide. Black layer comes on it.

And in case of copper, it reacts with carbon dioxide to form a layer named - copper carbonate.