When blood cells are placed in \(1\%\) (w/v) \(NaCl\) aqueous solution:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Cell will shrink
The fluid inside a blood cell has the same osmotic pressure as 0.9% (mass/volume) NaCl solution (normal saline). A 1% NaCl solution is more concentrated, so it is hypertonic to the cell. Water moves by osmosis from the cell (lower solute concentration) into the outside solution (higher solute concentration), and the cell loses water and shrinks.
Why the other options are incorrect
Option (1) Cell will burst — Incorrect. Bursting happens when so much water enters the cell that it ruptures; that needs a strongly hypotonic solution such as pure water.
Option (3) Cell will swell — Incorrect. A cell swells in a hypotonic solution (below 0.9% NaCl), where water flows into it.
Option (4) Cell remains as such — Incorrect. This is true only in an isotonic solution, 0.9% NaCl; 1% is not isotonic.
NCERT (2026-27 edition):
Osmosis and Osmotic Pressure – …
