Question

Qu7. The process due to which black layer on silver and green layer on copper is called​

Answer 1

Answer:

this process is called as oxidation

Answer 2

Answer:

the process is called Tarnishing

Explanation:

When silver is exposed to sulfur-containing gases in the air, it discolors and then darkens as it reacts with the gas to form a surface layer of tarnish. This process is called Tarnishing  

Copper combines with oxygen, carbon dioxide and water to form basic copper carbonate. This green layer is basic copper carbonate and this phenomenon is corrosion. Copper metal when exposed to air turns green in color due to corrosion.