Question -
Answer -
(i)┬аCH2Cl2
(ii)┬аCHCl3
(iii)┬аCCl4
Answer
(i)
Dichlormethane (CH2Cl2)
╬╝ = 1.60D
(ii)
Chloroform (CHCl3)
╬╝ = 1.08D
(iii)
Carbon tetrachloride (CCl4)
╬╝ = 0D
CCl4┬аis a symmetricalmolecule. Therefore, the dipole moments of all four CтИТCl 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 CтИТCl bonds is opposed by the resultantof dipole moments of one CтИТH bond and one CтИТCl bond. Since the resultant of oneCтИТH bond and one CтИТCl bond dipole moments is smaller than two CтИТCl bonds, theopposition is to a small extent. As a result, CHCl3┬аhasa small dipole moment of 1.08 D.
On the other hand, in case of CH2Cl2,the resultant of the dipole moments of two CтИТCl bonds is strengthened by theresultant of the dipole moments of two CтИТH bonds. As a result, CH2Cl2┬аhasa higher dipole moment of 1.60 D than CHCl3┬аi.e., CH2Cl2┬аhasthe highest dipole moment.
Hence, the given compounds can be arranged in theincreasing order of their dipole moments as:
CCl4┬а< CHCl3┬а2Cl2