Question

Why in humid atmosphere copper vessels get a green layer?

Answer 1

Here is your answer:

Copper metal when exposed to air turns green in color due to corrosion. Thus, when copper vessels are exposed to air in rainy season for sometime, the metal reacts with gases and moisture present in air to form a mixture of copper carbonate and copper hydroxide CuCO₃.

Answer 2

Copper metal when exposed to air turns green in color due to corrosion. sometime, the metal reacts with gases and moisture present in air to form a mixture of copper carbonate and copper hydroxide [{CuCO3]. Cu(OH)2]

This gives a green colour to the vessels.