Question -
Answer -
(i) CH2Cl2
(ii) CHCl3
(iii) CCl4
Answer
(i)
Dichlormethane (CH2Cl2)
μ = 1.60D
(ii)
Chloroform (CHCl3)
μ = 1.08D
(iii)
Carbon tetrachloride (CCl4)
μ = 0D
CCl4 is a symmetricalmolecule. Therefore, the dipole moments of all four C−Cl bonds cancel eachother. Hence, its resultant dipole moment is zero.
As shown in the above figure, in CHCl3,the resultant of dipole moments of two C−Cl bonds is opposed by the resultantof dipole moments of one C−H bond and one C−Cl bond. Since the resultant of oneC−H bond and one C−Cl bond dipole moments is smaller than two C−Cl bonds, theopposition is to a small extent. As a result, CHCl3 hasa small dipole moment of 1.08 D.
On the other hand, in case of CH2Cl2,the resultant of the dipole moments of two C−Cl bonds is strengthened by theresultant of the dipole moments of two C−H bonds. As a result, CH2Cl2 hasa higher dipole moment of 1.60 D than CHCl3 i.e., CH2Cl2 hasthe highest dipole moment.
Hence, the given compounds can be arranged in theincreasing order of their dipole moments as:
CCl4 < CHCl3 2Cl2