Which one of the following is used method to prepare the absolute alcohol.

Options

A. steam distillation
B. Azeotropic distillation
C. Vacuum distillation
D. None of the above

Answer

To prepare absolute alcohol, also known as anhydrous alcohol, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Absolute Alcohol**:
- Absolute alcohol is ethanol that contains no water. It is also referred to as anhydrous alcohol.

2. **Starting Material**:
- The preparation of absolute alcohol begins with rectified spirit, which is a mixture of ethanol and water. Rectified spirit is also known as an azeotropic mixture.

3. **Azeotropic Distillation**:
- The key method to separate ethanol from the azeotropic mixture is through azeotropic distillation. This method allows us to break the azeotropic nature of the mixture and obtain pure ethanol.

4. **Process of Azeotropic Distillation**:
- During azeotropic distillation, the rectified spirit is heated, and the vapor is collected and condensed. This process helps to separate the ethanol from water.

5. **Drying the Ethanol**:
- After azeotropic distillation, the resulting ethanol may still contain trace amounts of water. To remove this water, the ethanol is treated with a drying agent, such as fresh calcium oxide (CaO).

6. **Final Distillation**:
- The mixture is then distilled again to obtain absolute alcohol. This final distillation ensures that any remaining water is eliminated, resulting in pure ethanol.

### Final Answer:
The method used to prepare absolute alcohol is **azeotropic distillation**.

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