Question

Which one of the following has the highest dipole moment?

• A. ${\mathrm{CH}}_2{\mathrm{Cl}}_2$
• B. ${\mathrm{CHCl}}_3$
• C. ${\mathrm{CCl}}_4$

Answer 1

The correct option is A

${\mathrm{CH}}_2{\mathrm{Cl}}_2$

Explanation for correct option:

(A) ${\mathrm{CH}}_2{\mathrm{Cl}}_2$

Dipole moment:

• “Dipole moment is the product of the separation of the ends of a dipole and the value of charges.”
• In ${\mathrm{CH}}_2{\mathrm{Cl}}_2$, the resultant of two $\mathrm{C}-\mathrm{Cl}$ dipole moments gain more strength by the resultant moment of $\mathrm{C}-\mathrm{H}$ bonds.
• It has a dipole moment greater than the other two compounds.

Explanation for the incorrect options:

(B) ${\mathrm{CHCl}}_3$

• The resultant of two $\mathrm{C}-\mathrm{Cl}$ dipole moments is canceled by the resultant dipole moment of $\mathrm{C}-\mathrm{H}$ and $\mathrm{C}-\mathrm{Cl}$ bond, therefore decreasing the strength of the overall dipole moment.

(C) ${\mathrm{CCl}}_4$

• It is a symmetrical compound so it has a zero dipole moment.

Hence, the correct option is (A) i.e. ${\mathrm{CH}}_2{\mathrm{Cl}}_2$.