copper vessels get a green coat when exposed to air in rainy season
Copper metal when exposed to air turns green in colour 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). Cu(OH)2]. This gives a green colour to the vessels.
well i would like to clear out what gurleen has said:----Copper develops a strongly adhering oxide layer, which