Which is not used to purify organic solids ?

Options

A. Distillation
B. Sublimation
C. Crystallisation
D. None of these

Explanation

To determine which method is not used to purify organic solids, we can analyze the given options one by one:

### Step 1: Analyze Distillation
- **Definition**: Distillation is a technique used to separate components of a mixture based on differences in their boiling points.
- **Application**: It is primarily used for liquids. For example, if you have a mixture of chloroform (boiling point 60°C) and benzene (boiling point 80°C), distillation can separate them effectively.
- **Conclusion**: Distillation is not suitable for purifying organic solids.

### Step 2: Analyze Sublimation
- **Definition**: Sublimation is the process where a solid turns directly into vapor without passing through the liquid phase.
- **Application**: This method is used to purify certain organic solids like naphthalene and anthracene, which can be vaporized upon heating.
- **Conclusion**: Sublimation is indeed a method used to purify organic solids.

### Step 3: Analyze Crystallization
- **Definition**: Crystallization is a technique used to purify solid compounds by dissolving them in a suitable solvent and then allowing them to crystallize out.
- **Application**: This method is effective for separating solids from impurities that are soluble in the solvent used.
- **Conclusion**: Crystallization is also a method used to purify organic solids.

### Step 4: Analyze the Last Option - None of These
- **Definition**: This option suggests that none of the previous methods are suitable for purifying organic solids.
- **Conclusion**: Since both sublimation and crystallization are valid methods for purifying organic solids, this option is incorrect.

### Final Conclusion
Based on the analysis, the method that is **not** used to purify organic solids is **distillation**.

### Answer: Distillation

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