What would happen to the blood cells if they were placed in a 3% solution of sodium chloride?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → The cells would shrink.
In osmosis, water passes through a semipermeable membrane from the more dilute to the more concentrated solution. A 3% NaCl solution is more concentrated than the 0.9% NaCl solution that matches the fluid inside blood cells.
Why the other options are incorrect
Option (2) The cells would swell. — Incorrect. Swelling happens in a hypotonic solution, with less than 0.9% NaCl.
Option (3) No change. — Incorrect. This happens only in an isotonic solution, 0.9% NaCl.
Option (4) Sodium chloride will flow into the cells. — Incorrect. In osmosis only the solvent (water) moves through the membrane; the solute does not.
NCERT (2026-27 edition):
Osmosis and Osmotic Pressure – …
Note: The same/similar question has been asked in different years by NTA as per the details given below:
| 2026 | 2025 | 2024 | 2023 | 2022 |
|---|---|---|---|---|
| 22-05 S2 22-05 S1 | – | – | – | – |