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Stronger base of amine

wilson dang

please refer to the photo , the ans is A . why is it so ?

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Reply 1

charco

Study Forum Helper

Original post by wilson dang

please refer to the photo , the ans is A . why is it so ?

The lone pair on the nitrogen in B is conjugated with the rings pi system (delocalised) making it less available to behave as an electron pair donor...

Reply 2

indigobluesss

Original post by wilson dang

please refer to the photo , the ans is A . why is it so ?

Ok let's think for a minute. A base is a species that accepts/combines with a H+ ion or a species that donates a pair of electrons, right?

So a strong base will be able to pick up the hydrogen ion/form a more stable ion.

Both these molecules are rather similar with the difference that A has an added methyl group, and that's a massive difference! Because methyl (and other alkyl) groups tend to "push" electrons away from themselves.

That means there will be a slightly more negative charge in the nitrogen in A, this will mean it'll be able to accept H+ much more easily (because of difference in electrostatic attractions) and will form a much more stable compound with stronger bonds :smile: