rahul bought a statue made of copper. To his surprise it acquired a dull green coating after a couple of month. Explain the reason and name the process

The dull green coating is due to the corrosion of the copper in the surface of the statue.

Explanation:

The copper atoms in the surface of the statue were exposed to the air and rain during that period of time. The moisture and atmospheric gases react with the copper to produce a mixture of copper carbonate and copper hydroxide, that turns green the surface