Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).

Explanation

**Step-by-Step Solution:**

1. **Identify the materials**: The question compares copper and steel (an alloy of iron) for use in hot water tanks.

2. **Chemical reactivity**: Copper is known for its low reactivity with water, whether it is hot or cold. In contrast, iron (which is a major component of steel) reacts with steam.

3. **Reaction of iron with steam**: When iron is exposed to steam, it undergoes a chemical reaction that produces iron oxide and hydrogen gas. The reaction can be represented as:
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