Question

Assertion (A) : The volume of an ideal solution is equal to the sum of the volumes of the two components, i.e., \( \Delta_{mix}V = 0 \).

Reason (R) : The intermolecular forces of attraction between the solute-solvent molecules are weaker than those between the solute-solute and solvent-solvent molecules.

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

Hint:

In an ideal solution A-B forces equal A-A and B-B forces, so the assertion is true and the reason is false.

Answer 1

The Correct Option is C

Step 1: Recall the ideal solution:
An ideal solution obeys Raoult's law at all concentrations and temperatures.
For it, \( \Delta_{mix}H = 0 \) and \( \Delta_{mix}V = 0 \).

Step 2: Check the Assertion:
Since \( \Delta_{mix}V = 0 \), the volume of the solution equals the sum of the volumes of the components.
So Assertion (A) is true.

Step 3: Check the Reason:
In an ideal solution the A-B attraction is equal to the A-A and B-B attractions.
The Reason says the A-B attraction is weaker.
That describes a positive deviation from Raoult's law, which gives \( \Delta_{mix}V > 0 \).
So Reason (R) is false for an ideal solution.

Step 4: Choose the code:
A is true and R is false.
Codes (A), (B) and (D) are therefore wrong.

Final Answer:
Assertion is true and Reason is false, option (C). \[ \boxed{\text{(C)}} \]