Answer: Cu (OH)2. CuCO3
Cu (OH)2 is copper hydroxide
CuCO3 is a copper carbonate
A greenish coating that develops on copper utensils is due to the formation of copper hydroxide and copper carbonate [Cu (OH)2. CuCO3]
The greenish coating appears when copper utensils are exposed to air.
The reaction is as follows-
2Cu + H2O + CO2 + O2 → Cu (OH)2 + CuCO3
The copper utensils turn green in colour when exposed to air and this is due to corrosion.
A mixture of copper carbonate and copper hydroxide is formed when a metal reacts with moisture, gases including atmospheric gases