If the dipole moments of toluene and nitrobenzene are 0.43 D and 3.93 ...
The dipole moment of a molecule is the measure of its polarity. It is the product of the charge and the distance between the centers of positive and negative charges.
To find the expected dipole moment of p-nitrotoluene, we need to consider the dipole moments of toluene and nitrobenzene and the orientation of the nitro group in p-nitrotoluene.
- Toluene: Toluene is a nonpolar molecule with a benzene ring and a methyl group. The dipole moment of toluene is 0.43 D.
- Nitrobenzene: Nitrobenzene is a polar molecule with a benzene ring and a nitro group (-NO2). The dipole moment of nitrobenzene is 3.93 D.
- p-Nitrotoluene: p-Nitrotoluene is a molecule with a benzene ring, a methyl group, and a nitro group in the para position (opposite to the methyl group). The orientation of the nitro group in p-nitrotoluene affects its dipole moment.
The expected dipole moment of p-nitrotoluene can be calculated using the vector addition of the dipole moments of toluene and nitrobenzene. The direction of the dipole moment of nitrobenzene is opposite to the direction of the dipole moment of toluene due to the orientation of the nitro group.
- The dipole moment of toluene is 0.43 D.
- The dipole moment of nitrobenzene is 3.93 D in the opposite direction.
- The resultant dipole moment is the vector sum of the two dipole moments.
Using the vector addition formula, we get:
Resultant dipole moment = √(0.43^2 + 3.93^2 - 2 x 0.43 x 3.93 x cos 180°)
Resultant dipole moment = √(0.1849 + 15.4049 + 3.342) = √19.9318 = 4.46 D
Therefore, the expected dipole moment of p-nitrotoluene is 4.46 D, which is closest to option C (4.36 D).
If the dipole moments of toluene and nitrobenzene are 0.43 D and 3.93 ...
The total moment of the molecule, which is the vectorial sum of the individual bond moments. Thus, from the dipole moments of toluene and nitrobenzene, we should expect the moment of p-nitrotoluene to be ~ 4.36 D.
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