Chapter 11, Problem 11.61QP

Interpretation Introduction

Interpretation:

The heats of vaporization of liquid Chlorine, liquid Hydrogen and liquid Nitrogen are given.  These values are expected values has to be explained.

Concept introduction:

Larger size molecules have lesser interaction between nuclei and electrons.  Thus the electrons are free from nuclear force of attraction and easily form dipoles.  Thus, larger the size of the molecules, higher is the strength of London dispersion force.

$\text{London}\text{dispersion}\text{forces}\text{<}\text{Dipole-dipole}\text{forces}\text{<}\text{Hydrogen}\text{bonding}$

Both London dispersion forces and dipole-dipole forces do not exist permanently. London dispersion force is due to temporary dipole whereas dipole-dipole force is due to temporary dipole and remains longer time than the former one.  But hydrogen bonding exists permanently and thus it is the strongest among the intermolecular forces.