Question

Osmosis cannot be demonstrated by a potato osmoscope using a solution of NaCl instead of sugar; because the potato tissue is
A) Permeable to Na ion
B) Permeable to Cl ion
C) Permeable to the salt solution
D) Impermeable to the salt solution

Answer 1

Hint: Osmosis is a process in which solvent or water moves from a region of higher concentration to a region of lower concentration through a semipermeable membrane.

Complete answer: Osmotic pressure is defined as external pressure applied so there is no net movement of a solvent across the membrane. It is a colligative property, i.e., it depends on the molar concentration of solute.
Osmosis can be done in a system that is impermeable to the salt solution and permeable only to water. If a system is permeable to salts, we cannot differentiate the movement of water from outside to inside from the movement of salts from inside to outside or vice-versa. Since the potato tissue is impermeable to sugars, it should be used in a potato osmoscope.
Option A- Permeable to Na ion
The potato membrane is impermeable to sodium ions.
Option B- Permeable to Cl ion
Potato tissue is impermeable to chloride ions.
Option C- Permeable to the salt solution
Since potato tissue is permeable to the salt solution, osmosis cannot be performed using a salt solution.
Option D- Impermeable to the salt solution
As explained above, the salt solution is permeable to the potato membrane.

Thus, the correct option is Option C- Permeable to salt solution.

Note: Potato osmoscope is a method which is used, in which a sugar solution is placed inside a cavity prepared inside the potato tuber and is kept in water. After some time, water from the surrounding area cells enters the cavity, and the level of the solution in the cavity increases. This is because of osmosis. Due to osmosis, the mass of the potato decreases, and the potato shrinks.