Benzene and toluene do not have exactly the same intermolecular forces. Both have Van der Waals - London forces from temporary induced dipoles and toluene has also a slight dipole-dipole interaction from its very small dipole moment[toluene is small while benzene is vanishingly small effectively zero]. The difference in intermolecular attractions is not the force but the energy of attraction or the work required to separate the molecules. This energy is expressed in the heat of fusion and evaporation. If the forces are about equal, then the area in contact is determined by the molecular size and shape and these affect the energy of attraction. The differences in molecular sizes between toluene and benzene are apparent. Therefore very similar intermolecular forces result in different energies of attraction.

Finally, the boiling point or temperature of equilibrium depends on the heats and entropies of the transitions: at equilibrium delta H = Delta S T = Delta H/Delta S

Benzene and toluene do not have exactly the same intermolecular forces. Both have Van der Waals - London forces from temporary induced dipoles and toluene has also a slight dipole-dipole interaction from its very small dipole moment[toluene is small while benzene is vanishingly small effectively zero]. The difference in intermolecular attractions is not the force but the energy of attraction or the work required to separate the molecules. This energy is expressed in the heat of fusion and evaporation. If the forces are about equal, then the area in contact is determined by the molecular size and shape and these affect the energy of attraction. The differences in molecular sizes between toluene and benzene are apparent. Therefore very similar intermolecular forces result in different energies of attraction.

Finally, the boiling point or temperature of equilibrium depends on the heats and entropies of the transitions: at equilibrium delta H = T Delta S; T = Delta H/Delta S