The strength of dipole dipole forces depends upon the electro-negativity difference between the bonded atoms and the distance between the molecules. In gaseous state due to their intermolecular spaces there are weak dipole dipole forces while in liquid state due to their intermolecular spaces these forces are stronger than gases. HCl and CHCl3 (chloroform) are the examples. The strength of these forces also enhance the thermodynamic parameters like melting points, boiling points and heats of sublimation etc..