Question

copper utensils and sheets become blackidh aftr some days​

Answer 1

Answer:

Due to the formation of copper oxide on its surface

Explanation:

Cu + O2 ---->Cuo

Answer 2

Answer:

Copper utensils and sheets become black after some days because copper reacts with the carbon dioxide present in air to form copper carbonate. As a result they get corroded and this process is called corrosion.