Question

Arrange n-pentane, isopentane, and neopentane in the decreasing order of their boiling points and justify. [5 MARKS]

Answer 1

Order: 2 Marks
Structures: 1 Mark
Justification: 2 Marks

The decreasing order of boiling points is:
n-pentane>Isopentane>Neopentane
or


This is because, with the increase in branching, the surface area decreases. As a result of it, the magnitude of van der Waal's forces of attraction decreases, and therefore boiling point goes on decreasing.