Question

Write order of dipole moment of following compounds:

• A. $\left(iii\right)>\left(ii\right)>\left(i\right)>\left(iv\right)>\left(v\right)>\left(vi\right)$
• B. $\left(iii\right)>\left(i\right)>\left(ii\right)=\left(vi\right)>\left(iv\right)>\left(v\right)$
• C. $\left(ii\right)>\left(i\right)=\left(iii\right)=\left(iv\right)>\left(v\right)=\left(vi\right)$
• D. $\left(iii\right)>\left(i\right)>\left(iv\right)>\left(v\right)>\left(ii\right)>\left(vi\right)$

Answer 1

The correct option is C $\left(ii\right)>\left(i\right)=\left(iii\right)=\left(iv\right)>\left(v\right)=\left(vi\right)$

The decreasing order of dipole moment is
$\left(ii\right)>\left(i\right)=\left(iii\right)=\left(iv\right)>\left(v\right)=\left(vi\right)$
The dipole moments of $\left(v\right)=\left(vi\right)=0B.M$ because the individual bond dipoles cancel each other.
The dipole moments of $\left(i\right)=\left(iii\right)=\left(iv\right)$
In these molecules, the bond dipole of only one $C-Cl$ bond is not cancelled whereas the bond dipole of all other $C-Cl$ bonds is cancelled.
(ii) has highest dipole moment because the bond dipole of all three $C-Cl$ bonds is not cancelled.