Consider these statements about solutions formed by mixing two liquids: (A) An ideal solution obeys Raoult's law throughout the composition range. (B) A mixture of chloroform and acetone shows negative deviation from Raoult's law. (C) A mixture of aniline and phenol shows positive deviation from Raoult's law. The correct option is:

Solution & Explanation

Test each statement against Raoult's law and deviation rules (stronger A–B attraction than A–A/B–B ⇒ negative deviation; weaker ⇒ positive). (A) An ideal solution obeys Raoult's law over the whole composition range — this is the definition of ideality. Correct. (B) Chloroform + acetone: the chloroform H forms a new, stronger intermolecular H-bond with the acetone carbonyl, so A–B attraction exceeds the pure-liquid attractions ⇒ vapour pressure lower than predicted ⇒ negative deviation. Correct. (C) Aniline + phenol: these also form strong intermolecular H-bonds (phenolic O–H with the aniline N lone pair), giving stronger A–B attraction ⇒ negative deviation, NOT positive. So (C) is wrong. Hence only A and B are correct. Answer: option A.