Final answer:
In distillation, the first collected fraction is expected to contain a higher amount of hexane due to its lower boiling point and higher vapor pressure, while later fractions are expected to be enriched with toluene as the temperature of the mixture reaches toluene's higher boiling point.
Step-by-step explanation:
According to the distillation theory, when a mixture of two volatile liquids with notably different vapor pressures such as hexane and toluene is subjected to distillation, the relative amounts of each component in the collected fractions will differ based on their vapor pressures and boiling points. Hexane, being the more volatile compound with a lower boiling point than toluene, will vaporize first. As a result, the first fraction collected during the distillation process is expected to be richer in hexane, while the latter fractions would contain mostly toluene once the hexane has been largely vaporized and removed.
Using Raoult's law the vapor phase above a liquid solution is enriched in the component with the higher vapor pressure, which in this case is likely to be hexane. So, one would expect the mole fraction of hexane in the vapor to be greater than in the liquid phase. During fractional distillation, as the mixture is heated, the temperature reaches the boiling point of hexane first, causing it to vaporize and be collected as a distillate. Subsequent fractions would progressively contain more toluene and less hexane as the temperature rises towards toluene's higher boiling point and it starts to vaporize.