26. Copper substances when exposed to air gains a green coating due to the formation of: A.CuO B.CuCO3 Cu(OH)2 C.CuSO4 D.Cu(NO3)2
Answer: Option B Solution: When copper is exposed to air, it reacts with moist carbon dioxide in the air and slowly loses its shiny brown surface and gains a green coat. This green substance is basic copper carbonate (CuCO3. Cu (OH)2). The formation of this green coating on the surface of a copper object corrodes it.
