(a) Name an alloy of copper. State its chemical composition and any one use. (b) Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as?
(a) Name an alloy of copper. State its chemical composition and any one use. (b) Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as?

Solution:

(a) Brass: It is made up of 80 per cent copper (Cu) and 20 per cent zinc (Zn). It’s used to make kitchen utensils.

(b) Copper reacts slowly with carbon dioxide and water to form a basic copper carbonate coating on the object’s surface. This green covering of basic copper carbonate corrodes, and the process is known as copper corrosion.