In thistle funnel experiment, entry of water into thistle funnel stops after some time autumatically due to

Options

A. Diffusion of sugar out of thistle funnel
B. External and internal solutions become isotonic
C. Development of hyrostatic pressure in the thistle funnel
D. Development of gydrostatic pressure in the beaker.

Answer

**Step-by-Step Solution:**

1. **Understanding the Thistle Funnel Experiment**: The Thistle Funnel experiment is designed to demonstrate the process of osmosis, where water moves through a semi-permeable membrane from a region of lower solute concentration to a region of higher solute concentration.

2. **Setup of the Experiment**: In this experiment, a thistle funnel is filled with a concentrated sugar solution, and the opening of the funnel is covered with a goat bladder, which acts as a semi-permeable membrane.

3. **Initial Movement of Water**: When the experiment begins, water from the beaker (which has a lower concentration of solute) moves into the thistle funnel (which has a higher concentration of solute) through the semi-permeable membrane. This movement continues as water molecules diffuse into the funnel.

4. **Development of Hydrostatic Pressure**: As water enters the thistle funnel, the level of the sugar solution rises. This increase in liquid height creates hydrostatic pressure within the funnel. Hydrostatic pressure is the pressure exerted by a fluid at equilibrium due to the force of gravity.

5. **Equilibrium and Stopping of Water Entry**: Eventually, the hydrostatic pressure in the thistle funnel becomes equal to the osmotic pressure that is driving the water into the funnel. When these pressures balance out, the net movement of water stops, leading to an equilibrium state.

6. **Conclusion**: Therefore, the entry of water into the thistle funnel stops automatically due to the development of hydrostatic pressure in the thistle funnel.

**Final Answer**: The correct option is **C. Development of hydrostatic pressure in the Thistle Funnel**.

---