Molecules of hydrogen chloride, HCl, and molecules of fluorine, F2, contain the same number of electrons. Hydrogen chloride boils at –85 °C and fluorine boils at –188 °C.Explain why there is a difference in the boiling points of HCl and F2.

F2 has van der Waals’ forces, whilst HCl has permanent dipole–dipole attractions. Permanent dipole–dipole attractions are much stronger than induced dipoles. More enegery is required to break the stronger permanent dipole–dipole attractions, and therefore HCL has a higher boiling point.