In thistle funnel experiment, if sugar is added to beaker after the stoppage f osmosis, then

Options

A. Level of solution in beaker lowers
B. Level of solution in thishtle funnel rises up
C. Level of solution remins unaffected in beaker
D. Level of solution in thistle funnel lowers.

Answer

### Step-by-Step Solution:

1. **Understanding the Thistle Funnel Experiment**:
- The thistle funnel is filled with a sucrose solution and is placed in a beaker containing pure water. The mouth of the funnel is covered with a semi-permeable membrane (like parchment paper), which allows water to pass through but not the sucrose.

2. **Initial Observation**:
- Initially, when the experiment starts, water from the beaker moves into the thistle funnel through osmosis, causing the level of the sucrose solution in the funnel to rise. This occurs because water moves from an area of higher water concentration (the beaker) to an area of lower water concentration (the sucrose solution).

3. **Stoppage of Osmosis**:
- Osmosis will stop when the concentration of the sucrose solution in the funnel equals the concentration of water in the beaker. At this point, there is no net movement of water.

4. **Adding Sugar to the Beaker**:
- If sugar is added to the beaker after osmosis has stopped, the concentration of solute (sugar) in the beaker increases. This means the concentration of water in the beaker decreases compared to the concentration in the thistle funnel.

5. **Effect of Increased Sugar Concentration**:
- Due to the increase in sugar concentration in the beaker, water will now move from the thistle funnel (where the concentration of water is higher) to the beaker (where the concentration of water is lower). This process is called exosmosis.

6. **Resulting Changes**:
- As water moves out of the thistle funnel, the level of the solution in the thistle funnel will decrease. Conversely, the level of the solution in the beaker will increase as more water enters it.

7. **Conclusion**:
- Therefore, the correct answer to the question is that the level of solution in the thistle funnel lowers.

### Final Answer:
The correct option is that the level of solution in the thistle funnel lowers.

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