question about pyrrole

[ikulu]

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I understand that pyrrole is a poor base (from dat destroyer), so does it mean it's a strong acid?
I was thinking if the Nitrogen donates it's H+, it will become sp hybridizied (since it's lone pair is within the aromaticity system) and that just doesn't make sense to me.

Thanks for the help.

 

[ChrisM07]

You are right in that the H can be removed and thus will be acidic. However, according to the holy grail, Wikipedia, it appears that pyrrole is only moderately acidic with a pKa of 16.5.

You are also correct that when the H is removed, the lone pair that is left hanging out on the N will be taken into the ring and will contribute to the aromaticity. This is what makes it a weak base because the lone pair is spread out throughout the whole ring through resonance.