Which of the following processes is not responsible for the presence of electric charge on the sol particles ?

Options

A. Electron capture by sol particles
B. Adsorption of ionic species from solution.
C. Formation of Helmholtz electrical double layer.
D. Absorption of ionic species from solution.

Explanation

To determine which process is not responsible for the presence of electric charge on sol particles, we need to analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Sol Particles**:
- Sol particles are colloidal particles that are dispersed in a medium. They can carry an electric charge, which affects their stability and behavior in the solution.

2. **Option Analysis**:
- **Option 1: Electron capture by sol particle during electro-dispersion of metal**:
- When metal particles are dispersed in a solution, they can capture electrons, leading to a negative charge on the sol particles. This process contributes to the electric charge.

- **Option 2: Adsorption of ionic species from solution**:
- Ionic species in the solution can be attracted to the surface of sol particles and get adsorbed onto them. This adsorption can lead to a net charge on the sol particles, either positive or negative, depending on the nature of the ions.

- **Option 3: Formation of Helmholtz electrical double layer**:
- The Helmholtz electrical double layer forms at the interface of the sol particles and the surrounding medium. This layer consists of a charged layer of ions adsorbed onto the surface of the sol particles, contributing to the overall charge of the particles.

- **Option 4: Absorption of ionic species from solution**:
- Absorption typically refers to the process where a substance is taken up by another substance. In the context of sol particles, absorption does not directly contribute to the electric charge as it implies a more permanent incorporation rather than a surface interaction. Therefore, this process is less relevant to the presence of electric charge compared to the other processes mentioned.

3. **Conclusion**:
- Based on the analysis, **Option 4: Absorption of ionic species from solution** is not responsible for the presence of electric charge on the sol particles.

### Final Answer:
The process that is not responsible for the presence of electric charge on the sol particles is **absorption of ionic species from solution**.

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