Question

What property does fractional distillation rely on?

Answer 1

Fractional distillation relies on the property that each substance has a different boiling point and will turn into vapour and rise at different points in time. This is also how they are collected because of the difference in their boiling points. 
it is a process which separates a mixture into the elements that make up the mixture. The mixtures has to be heated to such high temperatures as is the boiling point of the elements in it so that all the elements boil and rise and can be distilled and collected separately.