Final answer:
PCl3, or Phosphorus trichloride, exhibits dipole-dipole attractions because it is a polar molecule with a trigonal pyramidal shape that results in a permanent dipole.
Step-by-step explanation:
Dipole-dipole interactions occur between molecules that are polar, where there is an unequal distribution of electrons resulting in a partial positive charge on one side and a partial negative charge on the other side of the molecule. This separation of charge is known as a dipole. Among the given options, PCl3 (Phosphorus trichloride) has such a dipole-dipole attraction. PCl3 is a polar molecule because of the difference in electronegativity between the phosphorus and the chlorine atoms and the trigonal pyramidal shape of the molecule, which does not allow the dipoles to cancel out. CO2 (Carbon dioxide) is linear and its dipoles cancel out, thus it is nonpolar. F2 (Fluorine gas) is a diatomic molecule of the same atom, hence it is nonpolar. Lastly, FeCl2 (Iron(II) chloride) is an ionic compound and its dominant forces are ionic bonds, not dipole-dipole attractions.