The dipole moment of o, p and m-dichlorobenzene will be in the order :

Options

A. `ogtpgtm`
B. `pgtogtm`
C. `mgtogtp`
D. `ogtmgtp`

Answer

To determine the order of dipole moments for ortho, para, and meta dichlorobenzene, we can follow these steps:

### Step 1: Draw the Structures
- **Ortho-dichlorobenzene (o-dichlorobenzene)**: The two chlorine atoms are attached to adjacent carbon atoms (1,2 positions).
- **Meta-dichlorobenzene (m-dichlorobenzene)**: The chlorine atoms are attached to carbon atoms that are one carbon apart (1,3 positions).
- **Para-dichlorobenzene (p-dichlorobenzene)**: The chlorine atoms are attached to opposite sides of the benzene ring (1,4 positions).

### Step 2: Analyze the Dipole Moments
- **Dipole Moment as a Vector Quantity**: The dipole moment is a vector quantity, meaning it has both magnitude and direction. The overall dipole moment of a molecule is determined by the vector sum of all individual bond dipoles.

### Step 3: Evaluate the Dipole Moments
- **Para-dichlorobenzene**: In the para configuration, the dipoles from the two chlorine atoms are equal in magnitude but opposite in direction, thus they cancel each other out. Therefore, the dipole moment is minimal (close to zero).

- **Meta-dichlorobenzene**: In the meta configuration, the dipoles do not cancel out completely. The angle between the dipole vectors is such that they add up to give a net dipole moment that is greater than that of para but less than that of ortho.

- **Ortho-dichlorobenzene**: In the ortho configuration, the two chlorine atoms create dipoles that do not cancel out completely. The bond angle is less than that in the meta configuration, which means the dipoles are more aligned and thus the resultant dipole moment is higher.

### Step 4: Conclusion
Based on the analysis:
- The dipole moment order from highest to lowest is:
- Ortho-dichlorobenzene > Meta-dichlorobenzene > Para-dichlorobenzene

Thus, the correct order of dipole moments is:
**Ortho > Meta > Para**