Which type of change is ‘Rusting of a metal’?

Options

A. Physical change
B. Chemical change
C. Both
D. None of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Rusting**: Rusting is a chemical process that occurs when iron reacts with oxygen and moisture in the environment. This reaction leads to the formation of a new substance known as iron oxide (commonly referred to as rust).

2. **Identifying the Type of Change**:
- A **physical change** is a change that does not alter the chemical composition of a substance. For example, melting ice into water is a physical change because the substance (H2O) remains the same.
- A **chemical change**, on the other hand, involves a transformation that results in the formation of one or more new substances with different chemical properties.

3. **Analyzing Rusting**: In the case of rusting:
- Iron (Fe) combines with oxygen (O2) from the air and water (H2O) to form iron oxide (Fe2O3·nH2O), which is a completely different substance from iron.
- This indicates that a chemical reaction has taken place, resulting in a new substance (rust).

4. **Conclusion**: Since rusting of iron leads to the formation of a new substance (iron oxide), it is classified as a **chemical change**.

**Final Answer**: Rusting of a metal is a chemical change.

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