Egg albumin is :

Options

A. Reversible colloid
B. Lyophilic colloid
C. Protective colloid
D. All

Answer

To determine the nature of egg albumin, we will analyze it based on the definitions and characteristics of the types of colloids mentioned in the question.

### Step-by-Step Solution:

1. **Identify the Nature of Egg Albumin**:
- Egg albumin is a protein found in egg whites. It is known for its ability to form a stable colloidal solution when mixed with water.

2. **Check if Egg Albumin is a Reversible Colloid**:
- A reversible colloid is one that can be transformed back to its original state after being dried or coagulated. Egg albumin can be dried and then re-dissolved in water, indicating that it is indeed a reversible colloid.

3. **Check if Egg Albumin is a Lyophilic Colloid**:
- Lyophilic colloids (or liquid-loving colloids) are those that have a strong affinity for the solvent (in this case, water). Egg albumin is soluble in water and forms a stable colloidal solution, confirming that it is a lyophilic colloid.

4. **Check if Egg Albumin is a Protective Colloid**:
- Protective colloids are typically lyophilic colloids that can stabilize lyophobic colloids (which do not have an affinity for the solvent). Since egg albumin is a lyophilic colloid, it can protect lyophobic colloids from coagulation, thus qualifying it as a protective colloid.

5. **Conclusion**:
- Based on the analysis, egg albumin is a reversible colloid, a lyophilic colloid, and also acts as a protective colloid. Therefore, the correct answer is "all of these".

### Final Answer:
Egg albumin is a reversible colloid, a lyophilic colloid, and a protective colloid. Hence, the correct option is "all of these".

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