[a confused chiral girl]

Hi,

I'm wondering which one of the following 3 is the most likely to donate a proton. I am thinking of C because that is the least basic, aka most acidic. that's because pyolle has pka of conj. acid 0.4 whereas the most basic is A because ammonia has pka of 9.26. Is this reasoning correct? so the  most likely to donate a proton would be C?

thanks!

[Yggdrasil]

(C) is the most likely to donate a proton because loss of a proton allows the pyrrole to become aromatic by freeing up the lone pair of the nitrogen and allowing it to delocalize.

The least aromatic should be (B) since the nitrogen is attached to two alkyl groups which act as electron donating groups.  Since these alkyl groups donate electron density, they help stabilize the positive charge on the nitrogen.  On the other hand, (A) is a primary amine, so there is only one electron donating group attached.  Therefore, the positive charge on the nitrogen in (A) is stabilized less than the positive charge on the nitrogen in (B).

[a confused chiral girl]

thank you  your explanation is ver complete and makes much more sense in understanding the concept than merely looking up the pkas