Imbibition causes -

Options

A. Increase in the volume of imbibant but no pressure development
B. Decrease in the volume of imbibant and pressure develops
C. No change in volume of imbibant but pressure develops
D. Volume of imbibant increases and pressure develops

Answer

**Step-by-Step Solution:**

1. **Define Imbibition**: Imbibition is the process of absorption of water by solids, particularly porous and hydrophilic solids.

2. **Identify Imbibent**: An example of an imbibent is dry wood. When dry wood is placed in water, it acts as a solid that absorbs water.

3. **Describe the Process**: When dry wood absorbs water, its size and volume increase. This phenomenon is known as swelling.

4. **Explain Pressure Development**: As water enters the imbibent (dry wood), it creates internal pressure. This pressure is referred to as imbibition pressure or matric potential.

5. **Evaluate the Options**:
- **Option 1**: Increase in the volume of imbibent, but no pressure development - Incorrect, because pressure does develop.
- **Option 2**: Decrease in the volume of imbibent and pressure develops - Incorrect, as the volume increases, not decreases.
- **Option 3**: No change in volume of imbibent, but pressure develops - Incorrect, since the volume does change (it increases).
- **Option 4**: Volume of imbibent increases and pressure develops - Correct, as both volume increases and pressure develops during imbibition.

6. **Conclusion**: The correct cause of imbibition is that the volume of the imbibent increases and pressure develops.