Give reasons for the following:
Iron is rendered passive with fuming nitric acid.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Reaction**: When iron (Fe) is placed in fuming nitric acid (HNO3), a chemical reaction occurs. Fuming nitric acid is a concentrated form of nitric acid that contains nitrogen dioxide (NO2) and is highly oxidative.

2. **Formation of Ferric Oxide**: As the iron reacts with the fuming nitric acid, it begins to oxidize and forms a layer of ferric oxide (Fe2O3) on its surface. This layer acts as a protective barrier.

3. **Passive Layer**: The ferric oxide layer that forms on the surface of the iron is non-reactive. This means that it does not interact with the nitric acid, preventing further oxidation of the underlying iron.

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