Question

Which of the following alkane has strong London dispersion forces?

Options

• n-Butane

• iso-Butane

• n-Pentane

• neo-Pentane

Answer 1

n-Pentane

Explanation:

The strength of London forces increases with increasing molecular mass. 

n-Pentane is longer and somewhat spread out, whereas neo-pentane is more spherical and compact. London dispersion forces are stronger in a long chain of atoms, where molecules are not compact. Hence, n-pentane has strong London dispersion forces.