Question

Which of the following represents the correct order of boiling points of the given substance?

• A. n-pentane > isopentane > neopentane
• B. isopentane > neopentane > n-pentane
• C. neopentane > n-pentane > isopentane
• D. n-pentane > neopentane > isopentane

Answer 1

The correct option is A n-pentane > isopentane > neopentane

$\text{Boiling point}\propto \frac{1}{\text{Branching in alkane}}$

In alkanes, the intermolecular forces are Van der waals forces which depend on the surface area. As the branching increases, the surface area decreases. Thus, the decrease in Van der waals forces results in the decrease in boiling point of the alkane.