Question

Copper loses its lustre due to the formation of greenish layer of copper ________ on its surface.

• A. oxide
• B. sulphate
• C. carbonate
• D. sulphite

Answer 1

The correct option is C carbonate

Carbon dioxide in moist air reacts with the surface of copper items. Copper loses its luster due to the formation of greenish layer of copper carbonate (${\text{CuCO}}_3$) on its surface. This is called
patination of copper.