At isoelectric point

Options

A. Colloidal sol becomes highly stable
B. Precipitation of a colloidal sol takes place
C. Colloidal particles becomes uncharged
D. Peptization can be carried out

Explanation

To solve the question regarding the isoelectric point, we will analyze the concept step by step.

### Step-by-Step Solution:

1. **Understanding Isoelectric Point (IEP)**:
- The isoelectric point is defined as the pH at which a particular molecule or surface carries no net electrical charge. This means that the positive and negative charges are balanced, resulting in electrical neutrality.

2. **Behavior of Colloidal Particles at IEP**:
- At the isoelectric point, colloidal particles in a solution become uncharged. This occurs because the surface charges on the particles neutralize each other.

3. **Stability of Colloidal Sols**:
- When colloidal particles are uncharged, they tend to aggregate or coalesce, leading to a decrease in stability of the colloidal sol. Therefore, the statement that "colloidal sol becomes highly stable" is incorrect.

4. **Reciprocal of Colloidal Sol**:
- The term "reciprocal" in this context is likely a typographical error or misunderstanding. At the isoelectric point, colloidal particles do not repel each other as they are uncharged, which can lead to precipitation rather than stability.

5. **Options Analysis**:
- Based on the understanding of the isoelectric point:
- **Option 1**: Colloidal sol becomes highly stable - Incorrect.
- **Option 2**: Reciprocal of colloidal sol takes place - Incorrect or unclear.
- **Option 3**: Colloidal particles become uncharged - Correct.
- **Option 4**: Application can be handled - Vague and not directly related to the IEP.

6. **Conclusion**:
- The correct answer to the question is **Option 3: Colloidal particles become uncharged** at the isoelectric point.