Which one of the following has the highest dipole moment?
(i) `CH_(2)Cl_(2) , (ii) CHCl_(3) , (iii) C Cl_(4)`

Explanation

(i). Tetrachloromethane `(C Cl_(4))` is a symmetrical molecule and has zero dipole moment.
(ii). In chloroform `(CHCl_(3))`, the resultant dipole momentu of two C-Cl bonds is opposed by resultant dipole moment of C-Cl and C-H bonds. since the latter resultant dipole moment is smaller, the molecule as a whole has dipole moment `(mu)=1*0.3D`.
(iii). In dichloromethane `(CH_(2)Cl_(2))`, the resultant dipole moments of two C-Cl and two C-H bonds reinforce one another. the molecule has maximum dipole moment `(mu)=1*62D`
`CH_(2)Cl_(2)` has the maximum dipole moment value.