The purification of the colloidal particles from crystalloid dimensions through semipermeable membrane is known as:

Options

A. Coagulation
B. Dialysis
C. Ultrafiltration
D. Peptization

Answer

To solve the question, "The purification of the colloidal particles from crystalloid dimensions through a semipermeable membrane is known as:", we will analyze the options provided and determine the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding the Terms**:
- **Colloidal Particles**: These are particles that are larger than molecules but smaller than visible particles, typically in the range of 1 nm to 1 µm.
- **Crystalloid**: Refers to true solutions where the solute particles are small enough to pass through a semipermeable membrane.
- **Semipermeable Membrane**: A barrier that allows certain particles to pass while blocking others based on size.

2. **Analyzing the Options**:
- **Option 1: Coagulation**: This process involves the aggregation of colloidal particles into larger particles that can settle out of the solution. This is not the correct answer since we are looking for a purification method.

- **Option 2: Dialysis**: This process involves the diffusion of ions or small particles through a semipermeable membrane. In dialysis, colloidal particles are retained while smaller crystalloid particles pass through, effectively purifying the colloidal solution. This matches the description in the question.

- **Option 3: Ultrafiltration**: This method uses a filter with pores that are larger than colloidal particles but smaller than crystalloid particles. It does not specifically refer to the process of purification through a semipermeable membrane as described in the question.

- **Option 4: Peptization**: This refers to the process of converting a precipitate back into a colloidal form using a peptizing agent. This is not relevant to the purification of colloidal particles.

3. **Conclusion**:
- After analyzing all the options, we find that **Option 2: Dialysis** is the correct answer. It accurately describes the process of purifying colloidal particles from crystalloid dimensions through a semipermeable membrane.

### Final Answer:
The purification of the colloidal particles from crystalloid dimensions through a semipermeable membrane is known as **Dialysis**.