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Question
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?
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Solution
Copper object, staying in damp air for a long time, reacts with carbon dioxide and moisture (water) in air slowly to form green layer of basic copper carbonate ( CuCO3. Cu(OH)2) on the outside area of the object. This process is known as corrosion. Copper is very low in its reactivity; therefore, corrosion of copper also occurs slowly.
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