If we heat iodine, then it is a

Options

A. physical change
B. chemical change
C. no change
D. colour change.

Explanation

To answer the question "If we heat iodine, then it is a...", we can analyze the process step by step:

### Step-by-Step Solution:

1. **Understanding the State of Iodine**:
- Iodine is a solid at room temperature. When we heat iodine, we need to observe what happens to it.

2. **Heating Iodine**:
- Upon heating, iodine undergoes a phase change. It transitions from a solid state to a gaseous state, forming iodine vapor.

3. **Phase Change**:
- This change from solid to gas is known as sublimation. Sublimation is a physical change where a substance changes directly from solid to gas without becoming a liquid.

4. **Condensation**:
- If we cool the iodine vapor, it can condense back into solid iodine. This indicates that the original substance (iodine) remains the same, just in a different state.

5. **Classification of Change**:
- Since there is no change in the chemical composition of iodine during this process (it remains iodine), and no new substance is formed, we classify this as a physical change.

6. **Conclusion**:
- Therefore, the answer to the question is that heating iodine results in a **physical change**.

### Final Answer:
If we heat iodine, then it is a **physical change**.

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