which of the following is not ?

Options

A. Gelatin sol
B. Silver sol
C. Sulphur sol
D. `As_(2)S_(3)` sol

Answer

To determine which of the following is not a lyophilic colloid, we first need to understand the definitions of lyophilic and lyophobic colloids.

### Step-by-Step Solution:

1. **Understanding Lyophilic Colloids**:
- Lyophilic colloids are those that have an affinity for the solvent, meaning they are solvent-loving. Examples include colloids formed from organic substances like gelatin, gum, starch, and proteins.

2. **Understanding Lyophobic Colloids**:
- Lyophobic colloids, on the other hand, do not have an affinity for the solvent and are considered solvent-hating. They are typically formed from inorganic substances. Examples include colloids of arsenic, ferric hydroxide, and platinum.

3. **Identifying the Options**:
- The question asks for the option that is not a lyophilic colloid. We need to identify which of the given options (not provided in the question) falls under the category of lyophobic colloids.

4. **Analyzing the Examples**:
- If the options include colloids like silver sol, sulfur sol, or arsenic sol, these would be classified as lyophobic because they are formed from inorganic substances and do not have a strong affinity for the solvent.

5. **Conclusion**:
- Based on the definitions and examples provided, the correct answer would be the colloid that is classified as lyophobic, as it does not exhibit the properties of a lyophilic colloid.

### Final Answer:
The colloid that is not lyophilic is the one that is classified as lyophobic, such as arsenic sol.