Why does benzene have a much higher boiling point (80 °C)than hexane (69 °C),even though they have the same number of carbons?
A)Benzene has fewer hydrogens than hexane.
B)Benzene is much more polar than hexane which enhances the attractive forces between molecules and raises the boiling point.
C)Benzene is planar and has delocalized electron density which increases the attractive forces between molecules and raises the boiling point.
D)Hexane has more Kekulé structures than benzene.
E)Benzene can covalently bond to another benzene molecule which increases its boiling point.

Question

Quizplus · Accepted Answer

Benzene is planar and has delocalized electron density which increases the attractive forces between molecules and raises the boiling point. This is due to the presence of pi bonds in benzene that contribute to a resonance structure, resulting in a delocalization of electron density across the entire molecule, which increases the London dispersion forces between adjacent molecules. Hexane, on the other hand, is a nonpolar molecule and has only weak London dispersion forces between its molecules. Therefore, the boiling point of benzene is higher than that of hexane. Choice A is incorrect because benzene has fewer hydrogens than hexane, but this does not explain the difference in boiling point. Choices B and E are incorrect because benzene and hexane are both nonpolar molecules, and they do not have significant dipole-dipole or hydrogen bonding forces. Choice D is unrelated to the boiling point difference between benzene and hexane.

Why Does Benzene Have a Much Higher Boiling Point (80