Choose the correct statement from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → The solution of benzene and toluene is an example of an ideal solution.
Benzene and toluene are very similar non-polar molecules, so the attractions between unlike molecules are nearly the same as between like ones and their solution is nearly ideal.
Why the other options are incorrect
Option (2) For an ideal solution, \(ΔH_{mix} > 0\). — Incorrect. For an ideal solution \( \Delta_{mix}H = 0 \); a positive value means heat is absorbed on mixing, which is a non-ideal solution with positive deviation.
Option (3) Ideal solutions do not obey Raoult's law. — Incorrect. Obeying Raoult's law at all concentrations is the very definition of an ideal solution.
Option (4) The solution of water and alcohol is an example of an ideal solution. — Incorrect. Water and ethanol are held by hydrogen bonds, and mixing changes these interactions, so the solution deviates from Raoult's law (positive deviation; it forms an azeotrope at about 95% ethanol).
NCERT (2026-27 edition):
Ideal Solutions
