The principal source of the difference in the normal boiling points of icl (97 °c; molecular mass 162 amu) and br2 (59 °c; molecular mass 160 amu) is both dipole-dipole interactions and london dispersion forces. the principal source of the difference in the normal boiling points of icl (97 °c; molecular mass 162 amu) and br2 (59 °c; molecular mass 160 amu) is both dipole-dipole interactions and london dispersion forces. true or false