Question

Which one of the following has the highest dipole moment?

(i)CH₂Cl₂

(ii)CHCl₃

(iii)CCl₄

• A. CH₂Cl₂
• B. CHCl₃
• C. CCl₄

Answer 1

The Correct Option is A

(i)

Dichlormethane(CH₂Cl₂) µ=1.60D
(ii)

Chloroform(CHCl₃) µ=1.08D
(iii)

Carbon tetrachloride(CCl₄)

µ=0D CCl₄ is a symmetrical molecule. Therefore, the dipole moments of all four C−Cl bonds cancel each other. Hence, its resultant dipole moment is zero. As shown in the above figure, in CHCl₃, the resultant dipole moments of two C−Cl bonds are opposed by the resultant dipole moments of one C−H bond and one C−Cl bond. Since the resultant of one C−H bond and one C−Cl bond dipole moment is smaller than two C−Cl bonds, the opposition is to a small extent. As a result,CHCl₃ has a small dipole moment of 1.08 D. the other hand, in the case of CH₂Cl₂, the resultant of the dipole moments of two C−Cl bonds is strengthened by the resultant of the dipole moments of two C−H bonds. As a result, CH₂Cl₂ has a higher dipole moment of 1.60 D than CHCl₃ i.e.,CH₂Cl₂ has the highest dipole moment. Hence, the given compounds can be arranged in the increasing order of their dipole moments as CCl₄<CHCl₃<CH₂Cl₂.