Question

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

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

Answer 1

The correct option is C Development of hydrostatic pressure in the thistle funnel

Osmosis plays an important role in the plant's growth, which helps in the transfer of water and minerals from the soil through the roots. The physiological process, osmosis can be demonstrated using thistle funnel experiment. Here in this experiment, the mouth of the thistle funnel is tied with a semipermeable membrane and it is filled with a sugar solution to a certain level. Then the thistle funnel is kept inverted inside of the beaker containing pure water. The initial level of sugar solution inside of the thistle funnel is noted. Now, water from the beaker starts to enter into the thistle funnel through the semipermeable membrane until an equilibrium is reached. Finally, the level of the solution inside the thistle funnel is increased. After some time upon reaching the equilibrium the level stops due to the development of hydrostatic pressure in the thistle funnel which is equal to the osmotic pressure.

So, the correct answer is option C.