Glycerol is separated in soap industries by :

Options

A. Fractional distillation
B. Distillation under reduced pressure
C. Differential extraction
D. Steam distillation

Explanation

To solve the question of how glycerol is separated in soap industries, we will analyze the options provided and determine the most suitable method for purifying glycerol.

### Step-by-Step Solution:

1. **Understanding the Properties of Glycerol**:
- Glycerol has a high boiling point (approximately 290°C or 563 K). This high boiling point can lead to decomposition if not handled properly during purification.

2. **Evaluating the Options**:
- **Distillation under reduced pressure**: This method, also known as vacuum distillation, lowers the boiling point of the substance by reducing the external pressure. This allows glycerol to be distilled at a lower temperature, preventing decomposition.
- **Fractional distillation**: This technique is used to separate components of a mixture based on differences in boiling points. However, it is not effective for glycerol due to its high boiling point and potential decomposition.
- **Differential extraction**: This method involves separating components using immiscible liquids. It is not suitable for glycerol as it does not effectively purify substances with high boiling points.
- **Steam distillation**: This technique is used for separating volatile compounds from non-volatile ones. Glycerol is sensitive to heat and can decompose, making steam distillation inappropriate.

3. **Conclusion**:
- The most effective method for purifying glycerol in soap industries is **distillation under reduced pressure**. This method allows glycerol to be distilled without decomposition by lowering its boiling point.

### Final Answer:
Glycerol is separated in soap industries by **distillation under reduced pressure**.

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