The incorrect statement about azeotropes is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → The components can be separated by fractional distillation.
An azeotrope has the same composition in the liquid and vapour phase, so distillation cannot change its composition. Examples: about 95% ethanol in water (minimum boiling, large positive deviation) and 68% nitric acid in water (maximum boiling, large negative deviation).
Option (1) They are binary mixtures of liquids. — A correct statement about azeotropes.
Option (2) The composition remains the same in liquid and vapour phase, at constant temperature. — A correct statement about azeotropes. This is what defines an azeotrope.
Option (3) The components can be separated by fractional distillation. — The incorrect statement. The vapour has the same composition as the liquid, so the components cannot be separated by fractional distillation.
Option (4) They show deviations from Raoult’s law. — A correct statement about azeotropes. Only non-ideal solutions with large deviations form azeotropes.
NCERT (2026-27 edition):
Non-ideal Solutions – …
