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Posted: Tue Nov 27, 2018 1:27 pm
In question 4.29, why does 1 have the largest dipole moment although the distance between the two chlorines is the smallest?
Posted: Tue Nov 27, 2018 8:34 pm
1 has the largest dipole moment because since the chlorines are positioned close to one side of the molecule, that side of the molecule will have a polarized charge in comparison to the other side with no chlorines. 3 has the smallest dipole moment because since the molecule is symmetrical, any charge the molecule might have would cancel each other out.
Posted: Wed Nov 28, 2018 12:26 pm
It is precisely because the two chlorines are positioned close together that they have the largest dipole moment, because then there is a stronger force of repulsion due to their close proximity. Figure 3 would have essentially no dipole moment, as the symmetry has the dipole moments "cancel each other out" so that the figure would be linear, is how I would interpret it.
Posted: Wed Nov 28, 2018 1:24 pm
I would always like to look at dipole moments as vectors. Looking at option 1, adding the two vectors (dipole moments) together gives us a resultant vector with a larger magnitude than the resultant vector for option 2.