A green layer is gradually formed on a copper plate left exposed to air for a week in a bathroom. What could this green substance be?

Dear student,

A green layer is gradually formed on a copper plate left exposed to air for a week in a bathroom. This green substance is known as corrosion. Corrosion is formed by the action of air and moisture on copper's surface. The green substance chemically is basic copper carbonate  (Cu ₂CO ₃(OH)₂).

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