Final answer:
The incorrect statement regarding fractional distillation is that the resulting distillate has the same composition as the original mixture. In reality, the composition changes as the process progresses and separation occurs.
Step-by-step explanation:
The statement regarding the fractional distillation of two substances that is not correct is: E. When the vapor at any stage of the distillation is condensed, the resulting distillate has the same composition as the original mixture of the two substances. Fractional distillation relies on the concept that when a mixture is heated, the substance with the lower boiling point and higher vapor pressure will be richer in the vapor phase than in the liquid phase, which allows for separation.
As the process continues, the composition of the liquid and vapor phases changes, and the resulting distillate will differ in composition from the original mixture. Therefore, the correct statements are that the substance with the lower boiling point has a higher concentration in the vapor than in the liquid (A), the boiling point of the mixture is not constant (B), the substance with the higher vapor pressure has a higher concentration in the vapor (C), and the mole ratio of the two substances in the vapor is not the same as it is in the liquid (D).