question_answer

The dipole moment of chlorobenzene is \[1.5D\]. The dipole moment of is

A)  \[2.86\,D\]                    

B)  \[2.25\,\,D\]

C)  \[1.5\,\,D\]                   

D)  \[0\,\,D\]

Correct Answer: C

Solution :

  Dipole moments of \[2Cl\] and \[5Cl\]are vectorically cancelled. It is duel \[l\] \[Cl\] and \[3\,\,Cl\] \[{{\mu }^{2}}\] \[=\mu _{1}^{2}+\mu _{2}^{2}+2{{\mu }_{1}}{{\mu }_{2}}\cos \theta \] \[={{(1.5)}^{2}}+{{(1.5)}^{2}}+2\times 1.5\times 1.5\times 1.5\cos \,120\]\[\therefore \] \[\mu =1.5D\]