A mixture of hexane (boiling point 69 °C) and toluene (boiling point 111 °C) is…
CHEMISTRY · Single correct · A Level · Chemistry · Alkanes · Alkanes
Problem
A mixture of hexane (boiling point 69 °C) and toluene (boiling point 111 °C) is separated by simple distillation. Which of the following best explains why hexane distills first?
(a) Hexane has a lower molar mass than toluene, so its molecules require less energy to vaporize and distill first.
(b) Hexane molecules form transient hydrogen bonds with one another, weakening the liquid structure and allowing them to vaporize sooner.
(c) Hexane experiences weaker intermolecular forces than toluene, giving it a higher vapor pressure at any given temperature.
(d) Hexane is more polar than toluene, so its molecules escape the liquid phase more easily and distill first.