Question

Among the following compounds, the one which shows highest dipole moment is

• A.
• B.
• C.
• D.

Answer 1

The Correct Option is D

The dipole moment of a compound is a vector quantity that depends on both the magnitude of the charge difference and the distance between the charges. In general, the dipole moment arises due to the difference in electronegativity between atoms and the asymmetry of the molecule's structure.

Given the compounds, one needs to analyze the structure for polarity and the electronegativity difference between the bonding atoms:

1. 

   This compound is p-Dichlorobenzene. The chlorine atoms are positioned opposite to each other, which cancels out their dipole moments due to symmetry. Thus, it has a low dipole moment.

2. 

   This compound is m-Dichlorobenzene. The chlorine atoms are positioned at the meta positions. Some cancellation occurs, but the dipole moment is greater than the para isomer. However, it is not the highest.

3. 

   This compound is o-Dichlorobenzene. The chlorine atoms are adjacent, leading to a partial cancellation of the dipole moment. The dipole moment is higher than the meta isomer but not the highest.

4. 

   This compound is Chlorobenzene. There is one chlorine atom attached, making it asymmetrical. The dipole moment is significant due to the strong difference in electronegativity between chlorine and hydrogen and no opposing effects from other substituents.

The highest dipole moment is observed in chlorobenzene. This is because there is only one chlorine atom, leading to no cancellation, and the entire charge difference leads to a single resultant vector.