Which of the following methods are used for resolution ?

Options

A. Biological methods by using special enzymes
B. By making their diastereomers
C. Chromatographic method using special absorbents
D. Azetotropic distillation

Answer

To solve the question "Which of the following methods are used for resolution?", we need to understand what resolution means in the context of chemistry and the methods that can be employed for this purpose.

### Step-by-Step Solution:

1. **Understanding Resolution**:
- Resolution refers to the process of separating a racemic mixture into its constituent enantiomers. A racemic mixture contains equal amounts of two enantiomers, which are non-superimposable mirror images of each other.

2. **Identifying the Methods**:
- We are given four methods to evaluate whether they are used for resolution or not.

3. **Method 1: Biological Method Using Special Enzymes**:
- This method is valid. Microorganisms such as bacteria and fungi can be used to selectively consume one enantiomer from a racemic mixture, thereby achieving resolution.

4. **Method 2: Making Diastereomers**:
- This method is also valid. By reacting a racemic mixture with a resolving agent, diastereomers can be formed. Diastereomers have different physical properties, allowing for their separation.

5. **Method 3: Chromatography Using Special Adsorbents**:
- This method is correct as well. In chromatography, one enantiomer can be selectively adsorbed onto an optically active support, allowing for the separation of the two enantiomers.

6. **Method 4: Azeotropic Distillation**:
- This method is incorrect for resolution. Azeotropic distillation is not a method used to separate enantiomers from a racemic mixture.

7. **Conclusion**:
- The correct methods for resolution are the first three: biological methods using special enzymes, making diastereomers, and chromatography using special adsorbents.

### Final Answer:
The methods used for resolution are:
1. Biological method using special enzymes
2. Making diastereomers
3. Chromatography using special adsorbents