Question

Which of the following experiment is called physiological demonstration of osmosis?

• A. Thistle funnel- whose mouth is tied with egg membrane
• B. Thistle funnel- whose mouth is tied with parchment paper
• C. Both A and B
• D. Bell jar experiment

Answer 1

Answer: (C)

Both A and B

Osmosis can be defined as movement of solvent from a dilute solution (high concentration of solvent) to concentrated solution (lower concentration of solvent)

Egg's membrane is a natural substance which act as semi-permeable membrane whereas parchment paper is a artificial substance which acts as semi-permeable membrane.

In Thistle funnel experiment, an egg's membrane/parchment paper is tied tightly around the mouth of the funnel with thread or rubber band. Now dilute sugar solution is carefully poured into the stem of the funnel to a certain level. The wide mouth of the funnel containing sugar solution is now kept in a beaker with the help of an Iron stand. Now 75% of the beaker is filled with water. A similar control setup also arranged but by taking plain water in the beaker and also plain water in Thistle Funnel. The apparatus are left undisturbed for 10 minutes. We find the level of sugar solution increases from its initial level in the experimental setup while there is no change in the level of water in the stem of Thistle Funnel in the control setup. This observation clearly indicates the movement of water molecules occurred from the beaker into Thistle Funnel in the case of experimental setup while in the control setup there is no movement of water molecules from beaker into Thistle Funnel through egg's membrane/parchment paper because both the solutions are of same concentration.

So, the correct answer is 'Both A and B'.