Question

Paheli bought a statue made of copper. To her surprise it acquired
a dull green coating after a couple of months. Explain the reason
NCERT Class VIII
Science - Exemplar Problems
Chapter 4. Materials: Metals and Non-Metals

Answer 1

heya...
here is Ur answer..
An important chemical property is the way copper reacts with oxygen. It turns the reddish-brown tint green. This change of color is a result of thecopper combining with water and carbon dioxide in moist air. The product of this reaction is called hydrated copper carbonate.

hope this helps you dear.....

Answer 2

This is due to a chemical process called rusting. When certain metals are kept in air or water their surface are covered with some of the impurities i. e. they react with each other chemically and form a product known as rust.
ex- Iron gets rusted when it is exposed to water and gets coated with a red brown powder sort of thing. The same is true for copper.
Hope It Helps