Import Question JSON

Let's analyze the dipole moments of the given molecules. **Benzene ($ \text{C}_6\text{H}_6 $):** Benzene is a highly symmetrical molecule (planar hexagonal structure). Due to its symmetry, the individual bond dipoles (C-H bonds are slightly polar, but their vector sum is zero) cancel each other out, resulting in a net dipole moment of zero ($ \mu = 0 $). **Chlorobenzene ($ \text{C}_6\text{H}_5 \text{Cl} $):** Chlorobenzene has a chlorine atom attached to the benzene ring. The C-Cl bond is polar due to the electronegativity difference between carbon and chlorine. This results in a net dipole moment for chlorobenzene (typically around 1.5 - 1.7 D). It is a polar molecule. **Isomers of Dichlorobenzene ($ \text{C}_6\text{H}_4 \text{Cl}_2 $):** There are three isomers of dichlorobenzene: ortho-dichlorobenzene, meta-dichlorobenzene, and para-dichlorobenzene. 1. **Ortho-dichlorobenzene (1,2-dichlorobenzene):** The two chlorine atoms are adjacent. The C-Cl bond dipoles are at an angle of 60° to each other. Their vector sum will be non-zero and relatively large, making ortho-dichlorobenzene a polar molecule with a significant dipole moment. 2. **Meta-dichlorobenzene (1,3-dichlorobenzene):** The two chlorine atoms are separated by one carbon atom. The C-Cl bond dipoles are at an angle of 120° to each other. Their vector sum will be non-zero, making meta-dichlorobenzene a polar molecule with a moderate dipole moment. 3. **Para-dichlorobenzene (1,4-dichlorobenzene):** The two chlorine atoms are directly opposite to each other. The C-Cl bond dipoles are equal in magnitude and point in exactly opposite directions (180° apart). Therefore, they cancel each other out completely, resulting in a net dipole moment of zero ($ \mu = 0 $). **Comparing Dipole Moments:** * **Equal dipole moment with $ \text{C}_6\text{H}_6 $ (Benzene):** Benzene has a zero dipole moment. Among the dichlorobenzene isomers, **para-dichlorobenzene** also has a zero dipole moment. * **Equal dipole moment with $ \text{C}_6\text{H}_5 \text{Cl} $ (Chlorobenzene):** Chlorobenzene has a non-zero dipole moment. Among the dichlorobenzene isomers, both ortho- and meta-dichlorobenzene have non-zero dipole moments. However, it's known that the dipole moment of **meta-dichlorobenzene** is approximately equal to that of chlorobenzene. For instance, chlorobenzene's dipole moment is about 1.5 - 1.7 D, and meta-dichlorobenzene's dipole moment is also in a similar range (e.g., ~1.68 D to 1.72 D). Therefore, the set of isomers of $ \text{C}_6\text{H}_4 \text{Cl}_2 $ that have an equal dipole moment with $ \text{C}_6\text{H}_5 \text{Cl} $ and $ \text{C}_6\text{H}_6 $ respectively, are meta-dichlorobenzene and para-dichlorobenzene. The correct answer is option 2.