The migration of positively charged colloidal particles, under an electrical field, towards the cathode is called

Options

A. Cataphoresis
B. Electro-osmosis
C. Sedimentation
D. Electro-dialysis

Answer

To solve the question regarding the migration of positively charged colloidal particles under an electric field towards the cathode, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept**:
- Colloidal particles can carry an electric charge. When an electric field is applied, these charged particles will migrate towards the electrode with the opposite charge.

2. **Identifying the Charge**:
- In this case, we are dealing with positively charged colloidal particles. According to the principles of electrostatics, positively charged particles will move towards the negatively charged electrode, which is the cathode.

3. **Defining the Process**:
- The movement of charged particles under the influence of an electric field is known as electrophoresis. Specifically, the migration of positively charged colloidal particles towards the cathode is a type of electrophoresis.

4. **Evaluating the Options**:
- The options given in the question include:
- a) Cataphoresis (also known as electrophoresis)
- b) Electroosmosis
- c) Sedimentation
- d) Electrodialysis
- Since we have established that the correct term for the migration of positively charged particles towards the cathode is cataphoresis (a type of electrophoresis), we can conclude that this is the correct answer.

5. **Final Answer**:
- Therefore, the migration of positively charged colloidal particles under an electrical field towards the cathode is called **cataphoresis**.