Question

hexane (c6h14) can exist in multiple isomers/forms. below are two different forms:
n-hexane:
ch₃—ch₂—ch₂—ch₂—ch₂—ch₃

neohexane:
ch₃
|
ch₃—c—ch₂—ch₃
|
ch₃
based on these structures, which isomer/form would have the higher boiling point,
and why?
○ n-hexane because the molecules are longer and less compact (higher surface
area)
○ n-hexane because the molecules have a stronger permanent dipole
○ neohexane because the molecules are shorter and more compact (smaller
surface area)
○ neohexane because the molecules have a larger, more polarizable electron
cloud.

Explanation:

Hexane isomers have London dispersion forces. Boiling point depends on surface area for non - polar molecules (both are non - polar as they are hydrocarbons). n - Hexane is a straight - chain alkane, so its molecules are longer and less compact, leading to a larger surface area. A larger surface area means stronger London dispersion forces, which require more energy to break, resulting in a higher boiling point. Neohexane is branched, so it has a smaller surface area. The option about permanent dipole is wrong as alkanes are non - polar. The options favoring Neohexane are wrong because smaller surface area (more compact) leads to weaker forces and lower boiling point, and electron cloud polarizability isn't the main factor here compared to surface area.

Answer:

A. n - Hexane because the molecules are longer and less compact (higher surface area)