In lyophilic sols the attraction of sol particles towards the medium is due to

Options

A. Covalent bond
B. Vander Waal's force
C. Hydrogen bond
D. None of these

Explanation

To solve the question regarding the attraction of sol particles in lyophilic sols, we will analyze the options provided and understand the nature of lyophilic sols.

### Step-by-Step Solution:

1. **Understanding Lyophilic Sols**:
- Lyophilic sols are colloidal systems where the dispersed phase (sol particles) has a strong affinity for the dispersion medium (the solvent). This affinity is crucial for the stability of the sol.

2. **Identifying Forces of Attraction**:
- The attraction between sol particles and the medium can arise from various types of intermolecular forces. The options provided include:
- Covalent bonds
- Van der Waals forces
- Hydrogen bonds
- None of these

3. **Evaluating Each Option**:
- **Covalent Bonds**: These are strong bonds formed by the sharing of electrons between atoms. They are not typically responsible for the attraction in colloidal systems.
- **Van der Waals Forces**: These are weaker intermolecular forces that can contribute to attraction but are not the primary reason for the stability of lyophilic sols.
- **Hydrogen Bonds**: These are a specific type of dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative atoms (like oxygen or nitrogen). In lyophilic sols, hydrogen bonding can occur between the sol particles and the solvent, providing significant attraction.
- **None of These**: This option would imply that none of the previous forces are responsible, which is not accurate in the case of lyophilic sols.

4. **Conclusion**:
- Based on the analysis, the primary attraction of sol particles towards the medium in lyophilic sols is due to hydrogen bonding. Therefore, the correct answer is **hydrogen bond**.

### Final Answer:
The attraction of sol particles towards the medium in lyophilic sols is due to **hydrogen bonding**.

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