Which one of the following has the highest dipole moment ?

Explanation

`C CI_(4)`(c) is symmetrical and has resultant zero dipole moment. In `CHCl_(3)` (b), the resultant of two C-Cl dipoles is opposed by resultant of C-H and C-Cl bonds. Since the latter resultant is expected to be smaller than the former, `CHCl_(3)` has a definite dipole moment. It has been found to have dipole moment of 1.03D. In `CH_(2)Cl_(2)` (a), the resultant al two C-Cl bonds is reinforced by the resultant af two C-H dipoles and therefore, it has a higher dipole moment than `CHCl_(3)` It has been found to have dipole moment of 1.620.
Thus, `CH_(2)Cl_(2)` has the highest dipole moment.