Question

Assertion (A): Blood cells collapse when suspended in saline water.
Reason (R): Cell membrane dissolves in saline water.

• A. Both (A) and (R) are correct and R is the correct explanation of A
• B. Both (A) and (R) are correct, but R is not the correct explanation of A
• C. (A) is correct but (R) is not correct
• D. (A) is incorrect but (R) is correct

Hint:

In a hypertonic solution, water moves out of the cell by osmosis, causing the cell to shrink.

Answer 1

The Correct Option is C

Step 1: Recall the idea of osmosis.
Water always moves across a semipermeable membrane from the side of higher water concentration (dilute) towards the side of lower water concentration (concentrated).
Step 2: Compare blood cell fluid with saline water.
When the saline water outside is more concentrated than the fluid inside the blood cell, the outside has less free water than the inside.
Step 3: Predict the direction of water flow.
Therefore water leaves the cell and moves out into the saline solution, since water heads towards the more concentrated side.
Step 4: Judge Assertion (A).
Losing water makes the cell shrink and collapse, so the statement that blood cells collapse in saline water is correct.
Step 5: Judge Reason (R).
The membrane does not dissolve. It stays intact and simply lets water pass through, so the reason is incorrect. The collapse is purely an osmotic effect.
Step 6: Combine the verdicts.
Assertion is correct but the reason is wrong, which matches option 3.
\[ \boxed{\text{(A) is correct but (R) is not correct}} \]