Paheli bought a statue made of copper. To her surprise it acquired a dull green coating after a couple of months. Explain the reason.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Material**: Paheli bought a statue made of copper. Copper is a metal known for its reddish-brown color and is often used in various applications, including decorative items like statues.

2. **Reactivity of Copper**: Copper has low reactivity compared to other metals. However, it can still react with substances in its environment, particularly oxygen and moisture present in the air.

3. **Formation of Copper Oxide**: When the copper statue is exposed to air, it reacts with oxygen to form copper oxide (CuO). This process is known as oxidation.

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