An iron nail is kept in each of the following liquids. In which case would it lose its shine and appear dull?

Options

A. Mustard oil
B. Soft drink
C. Cocount oil
D. Kerosene

Explanation

To determine in which case an iron nail would lose its shine and appear dull when placed in different liquids, we can analyze the effects of each liquid on the iron nail.

### Step-by-Step Solution:

1. **Identify the Liquids**: The question mentions several liquids: mustard oil, coconut oil, kerosene, and soft drinks.

2. **Understand the Properties of Each Liquid**:
- **Mustard Oil, Coconut Oil, Kerosene**: These are all types of oils. Oils generally do not react with iron and can act as lubricants. They help to prevent oxidation and corrosion of the iron surface, allowing the nail to retain its shine.
- **Soft Drinks**: Soft drinks contain carbonic acid and are often carbonated (contain compressed gases). The acidic nature and the presence of gases can lead to corrosion of the iron.

3. **Analyze the Effect on the Iron Nail**:
- When an iron nail is placed in **mustard oil, coconut oil, or kerosene**, it will **retain its shine** because these substances do not corrode the iron.
- When an iron nail is placed in a **soft drink**, the acidic content and the compressed gases can cause the iron to corrode, leading to the nail losing its shine and appearing dull.

4. **Conclusion**: The iron nail will lose its shine and appear dull when placed in **soft drinks**.

### Final Answer:
The iron nail will lose its shine and appear dull when kept in **soft drinks**.

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