ANS:C - same as liquid composition.

In an azeotropic mixture, the equilibrium vapor composition is the same as the liquid composition. Azeotropic mixtures are special mixtures of two or more components that boil at a constant temperature and have constant composition in both the liquid and vapor phases during the entire boiling process. As a result, the vapor composition at equilibrium is identical to the liquid composition. This characteristic distinguishes azeotropic mixtures from other binary or multicomponent mixtures where the vapor and liquid compositions typically differ at equilibrium. Therefore, the correct statement is: In an azeotropic mixture, the equilibrium vapor composition is the same as the liquid composition.