If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of

(A) CuSO 4

(B) CuCO 3

(C) Cu(NO 3 ) 2

(D) CuO



Copper corrodes in the presence of air and moisture

Because of the CO 2 and O 2 present in the air, Cu reacts with them to form CuCO 3  which is green in color.

The reactions take place as:


So, the correct answer is (b) CuCO 3

  1. Class 10
  2. Chapter 3 Class 10 - Metals and Non-Metals (Term 1)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo