The best method for the separation of naphthalene and benzoic acid from their mixture is

Options

A. chromatography
B. crystallisation
C. distillation
D. sublimation

Explanation

To solve the problem of separating naphthalene and benzoic acid from their mixture, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Properties of the Compounds**:
- Naphthalene is a solid at room temperature and has the ability to sublime, which means it can transition directly from a solid to a gas upon heating without becoming a liquid.
- Benzoic acid, on the other hand, does not sublime under normal conditions and will remain solid when heated.

2. **Choosing the Separation Method**:
- Given the properties of both compounds, sublimation is the most effective method for separation. This is because naphthalene can be heated to produce vapors, while benzoic acid will not vaporize and will remain in the solid state.

3. **Setting Up the Apparatus**:
- To perform sublimation, set up a heating apparatus where the mixture of naphthalene and benzoic acid is placed in a container that can be heated.
- Use an inverted funnel or a similar apparatus to collect the vapors of naphthalene. The funnel should be placed above the mixture to capture the sublimated naphthalene.

4. **Heating the Mixture**:
- Gradually heat the mixture. As the temperature rises, naphthalene will begin to sublime, turning into vapor.
- The vapor will rise and condense on the cooler surface of the inverted funnel, where it will solidify back into naphthalene.

5. **Collecting the Products**:
- After sufficient heating, turn off the heat and allow the apparatus to cool.
- Collect the solidified naphthalene from the inverted funnel.
- The benzoic acid will remain in the original container, thus achieving separation.

### Final Conclusion:
The best method for the separation of naphthalene and benzoic acid from their mixture is **sublimation**.

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