Which of the following statements are true for ideal solutions?
(A) The solutions obey Raoult’s law over the entire range of concentration.
(B) The change in entropy of mixing of the pure components to form the solution is zero.
(C) The change in volume of mixing of the pure components to form the solution is zero.
(D) The solutions obey Raoult’s law only in low concentrations.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A) and (C) only
An ideal solution obeys Raoult’s law over the entire range of concentration.
(A) The solutions obey Raoult’s law over the entire range of concentration. — Correct. This is the definition of an ideal solution.
(B) The change in entropy of mixing of the pure components to form the solution is zero. — Incorrect. Mixing makes the arrangement of molecules more random, so the entropy of mixing is positive, not zero.
(C) The change in volume of mixing of the pure components to form the solution is zero. — Correct. For an ideal solution ΔmixV = 0 (and ΔmixH = 0).
(D) The solutions obey Raoult’s law only in low concentrations. — Incorrect. An ideal solution obeys the law over the entire range of concentration, not only when dilute.
NCERT (2026-27 edition):
Ideal and Non-ideal Solutions
