CHCl3 has the highest dipole moment. The reason for it can be understood by looking into the structure of the given compounds.
(i) CH2Cl2 has a symmetrical structure such that the C−Cl bond dipole moments cancel out each other while theC−H dipole moments reinforce each other and thus contribute to a net moment.(ii) CCl4 has a perfectly tetrahedral structure where the net dipole of 3 C – Cl bonds point in a direction opposite to the fourth C – Cl bond and thus results in zero dipole moment.(iii) In CHCl3 net moment of 3C–Cl reinforces the dipole moment of C–H and therefore has the highest dipole moment.