Question

Give the name of the compound that covers the surface when the following metal are exoposed to the air for a long time (1) copper (2)silver

Answer 1

Answer:

1. copper reacts with oxygen to form copper oxide.

2. silver reacts with sulphide gas to form silver sulphide.

Answer 2

Answer:

1)Copper reacts with moisture carbon dioxide and oxygen to form a green coat of basic copper carbonate having formula CuCO3.Cu(OH)2

{ you have to note here that copper oxide is not formed here because copper oxide is formed by heating copper in presence of air (oxygen)}

2)Silver acquire a black coat of silver sulphide due to the reaction of sulphur gas with silver.

Formula of silver sulphide is Ag2S.