Question

Among the intermolecular forces, which forces are typically the weakest?

Answer 1

The London dispersion forces are generally the weakest intermolecular forces, although this can depend on the specific molecules and their state. This is a fluctuating attraction force between temporary dipoles on nonpolar molecules. 

Answer 2

The strength of intermolecular forces from the strongest to the weakest is:-

Hydrogen Bonds > Dipole-Dipole interactions > Dipole-induced dipole > London dispersion forces

Hence, London dispersion forces are the weakest. This arises due to the unsymmetrical distribution of electrons around the nucleus which tends to create an instantaneous temporary dipole. When a second molecule come in contact, the dipole from the first distorts the charge distribution in the later which leads to weak electrostatic attraction between the two atoms/molecules.