JEE Main 2023 — Haloalkanes And Haloarenes Question with Solution

The correct option from the pairs having both compounds with a net non-zero dipole moment is:

Option A: $\text{cis-butene, trans-butene}$ cis-butene has a net dipole moment because the two alkyl groups are on the same side of the molecule, causing an imbalance in the distribution of electrons. However, trans-butene is symmetric, so the dipole moments of the two alkyl groups cancel each other out, giving it a net dipole moment of zero. Therefore, this pair does not have both compounds with a net non-zero dipole moment.

Option B: ${\text{CH}}_2{\text{Cl}}_2,{\text{CHCl}}_3$ Both ${\text{CH}}_2{\text{Cl}}_2$ (dichloromethane) and ${\text{CHCl}}_3$ (chloroform) have a net non-zero dipole moment due to the difference in electronegativity between the hydrogen and chlorine atoms. Hence, this pair has both compounds with a net non-zero dipole moment.

Option C: $\text{Benzene, Anisidine}$ Benzene has a symmetrical structure, leading to a net zero dipole moment. Anisidine, however, does have a net dipole moment due to the asymmetry in its structure. Therefore, this pair does not have both compounds with a net non-zero dipole moment.

Option D: $\text{1,4-Dichlorobenzene, 1,3-Dichlorobenzene}$ $\text{1,4-Dichlorobenzene}$ has a symmetrical structure, leading to a net zero dipole moment. However, $\text{1,3-Dichlorobenzene}$ has a non-zero dipole moment due to the asymmetry in its structure. Therefore, this pair does not have both compounds with a net non-zero dipole moment.