Question

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

Options

• CuSO₄

•  CuCO₃

• Cu(NO₃)₂

• CuO

Answer 1

CuCO₃

Explanation - 

Copper metal kept open in the air, slowly undergoes the process of corrosion to form a characteristic blue-green coating on top of the metal surface. The corrosion of copper metal in air occurs in several steps : 

`4"Cu"("s") + "O"_2("g") -> 2"Cu"_2"O"("s"),` red colour

`"Cu"_2"O"("s") + "O"_2("s") -> 2"CuO"("s"),` black colour

`2"CuO"("s") +  "CO"_2("g") + "H"_2"O"("l") -> "CuCO"_3("s") + "CuCO"_3("s") + "Cu"("OH")_2("s"),` green colour