Pressure potential in thistle funnel develop

Options

A. Before the addition of solute
B. After the addition of solute
C. Before the entry of water
D. After the entry of water in the thistle funnel

Answer

### Step-by-Step Solution:

1. **Understanding the Thistle Funnel Experiment**:
- The thistle funnel experiment is designed to demonstrate osmosis and the development of pressure potential. It consists of a thistle funnel filled with a sugar solution and submerged in a beaker of pure water.

2. **Initial Conditions**:
- Before any water enters the thistle funnel, we have a sugar solution in the funnel and pure water in the beaker. At this stage, there is no pressure potential because there is no movement of water.

3. **Addition of Water**:
- When water from the beaker begins to enter the thistle funnel, it moves through the semi-permeable membrane. This movement occurs due to the concentration gradient between the pure water (low solute concentration) and the sugar solution (high solute concentration).

4. **Development of Pressure Potential**:
- As water enters the funnel, it dilutes the sugar solution, increasing the volume of liquid inside the funnel. This influx of water creates pressure against the walls of the funnel, leading to the development of pressure potential.

5. **Equilibrium**:
- Over time, the concentration of the sugar solution will change as water continues to enter until an equilibrium is reached. At this point, the pressure potential will have been established due to the influx of water.

6. **Conclusion**:
- The pressure potential in the thistle funnel develops **after the entry of water** into the funnel. Therefore, the correct answer is that pressure potential develops after the addition of water.