ochem-polarity question

[dl9006]

which is more apolar and why?

a) a benzene ring with 2 ester groups para to each other

b) a benzene ring with 2 amines para to each other


ans:a

(from topscore btw)

i know ester molecule is apolar but isn't the molecule with amine groups pretty apolar too?

does it have to do with the lone pair on the amines?

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[azar87]

the amines are more electronegative than the ester group thats why they would be polar and the ester groups wouldn't be

 

[Sublimation]

since the two amines are para to one another we have symmetry thus decreasing the polarity the first example has a dipole due to the lack of symmetry this would be my reasoning

yup i second this. the ester has a carbonyl that is planar and will have a dipole that will give u a net dipole in the molecule even though it is polar. now in the case of the amine you have the lone pairs having the dipoles in opposite directions thus you will have them cancel. This is a poor question cuz you have to assume that the carbonyl are facing the same direction < dont dwell on that i wont be able to explain it without drawing it lol.