there are three different dichloroethylenes (molecular formula c2h2cl2), which we can designate x, y, and z. compound x has no dipole moment, but compound z does. compounds x and z each combine with hydrogen to give the same product: c2h2cl2(x or z) h2 → clch2―ch2cl what are the structures of x, y, and z? be sure to include lone pair electrons.