Which is not a characteristic of imbibition ?

Options

A. It is a reversible phenomenon
B. Heat is generated
C. Involves both capillarity and adsorption
D. It is a property of hydrophobic and lyophobic colloids

Answer

To determine which option is not a characteristic of imbibition, we need to first understand what imbibition is and its properties.

### Step-by-Step Solution:

1. **Definition of Imbibition**:
- Imbibition is the process by which solid particles absorb water without forming a solution. This process typically involves the absorption of water by hydrophilic (water-attracting) materials.

2. **Characteristics of Imbibition**:
- Imbibition is generally a reversible phenomenon. This means that the absorbed water can be released back into the environment.
- During imbibition, heat is generated due to the absorption process, which is a characteristic of this phenomenon.
- Imbibition involves the interaction of water with hydrophilic colloids, not hydrophobic ones.

3. **Analyzing the Options**:
- **Option A**: "Irreversible phenomena" - This is incorrect because imbibition is reversible.
- **Option B**: "Heat is generated" - This is a characteristic of imbibition.
- **Option C**: "Involves both capillaries and absorption" - This is also a characteristic of imbibition.
- **Option D**: "It is a property of hydrophobic colloid" - This is incorrect because imbibition is associated with hydrophilic colloids, not hydrophobic ones.

4. **Conclusion**:
- The option that is not a characteristic of imbibition is **Option D**: "It is a property of hydrophobic colloid."

### Final Answer:
The correct answer is **Option D**: "It is a property of hydrophobic colloid."

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