Which of the following statements is/ are correct?
(A) For an ideal solution, the enthalpy and volume of mixing of pure components are zero.
(B) The inter-molecular attractive forces between A-A and B-B are greater than those between A-B for an ideal binary solution.
(C) The inter-molecular attractive forces between A-A and B-B are of the same order as those between A-B for an ideal binary solution
(D) For an ideal solution, the enthalpy and volume of mixing of pure components to form the solution are positive.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A) and (C) only
An ideal solution obeys Raoult’s law over the whole range of concentration, and for it:
\( \displaystyle \Delta_{\text{mix}}H = 0, \qquad \Delta_{\text{mix}}V = 0 \)
(A) For an ideal solution, the enthalpy and volume of mixing of pure components are zero. — Correct. These are the two properties of an ideal solution besides obeying Raoult’s law.
(B) The inter-molecular attractive forces between A-A and B-B are greater than those between A-B for an ideal binary solution. — Incorrect. Weaker A–B forces describe a non-ideal solution with positive deviation, such as ethanol and acetone.
(C) The inter-molecular attractive forces between A-A and B-B are of the same order as those between A-B for an ideal binary solution — Correct. This is the molecular condition for ideal behaviour.
(D) For an ideal solution, the enthalpy and volume of mixing of pure components to form the solution are positive. — Incorrect. Both are zero; positive values are found in solutions showing positive deviation.
NCERT (2026-27 edition):
Ideal Solutions
