Question

Which of the following compounds have dipole moment approximately equal to half of chlorobenzene?
A. o-dichlorobenzene
B. m-dichlorobenzene
C. p-dichlorobenzene
D. p-chloronitrobenzene

Answer 1

This question gives the knowledge about dipole moment and electronegativity. Dipole moment is defined as the product of distance between the centers of two charges and the magnitude of separated charge.

Complete step by step answer:
Dipole moment is defined as the product of distance between the centers of two charges and the magnitude of separated charge. It is represented by the symbol $\mu$. Dipole moment is used to determine the polarity of the overall system. The SI unit of dipole moment is coulomb meter or Debye. Dipole moment is a vector quantity that always undergoes a cross product. The molecules which have linear structure possess zero dipole moment.
There are various factors which affects the dipole moment of a molecule are as follows:
- The diatomic molecules which contain identical atoms possess zero dipole moment whereas the diatomic molecules which contain non-identical atoms do not possess zero dipole moment because polarity is generated in that molecule.
- The molecules which have linear structure possess zero dipole moment whereas the molecules which have non-linear structure do not possess zero dipole moment. This shows the dipole moment depends upon the geometry of the molecule.
- Molecules with electronegative atoms possess more dipole moments as compared to other molecules with no electronegative atoms.
- O-dichlorobenzene possesses dipole moment approximately equal to half of chlorobenzene because when we half the dipole moment of chlorobenzene it turns out to be equal to the resultant dipole moment of o-dichlorobenzene.
Therefore, the option is, ‘A. o-dichlorobenzene’ correct.

Note: Always remember that dipole moment is defined as the product of distance between the centers of two charges and the magnitude of separated charge. Dipole moment is a vector quantity. The molecules which have linear structure possess zero dipole moment.