Question

Rank the following nitrogen-containing aromatic molecules in order of increasing basicity.

Answer 1

Pyridine is more basic than pyrrole, as pyrrole is aromatic and more stable due to conjugation of lone pair on N atom with two double bonds. Where as pyridine has stable three double bonds and donate easily lone pair of electrons and thus more basic NH Pyridine pyrrole Electron withdrawing group (Br) on 3-bromopyridine, makes it less basic than pyridine Electron donating group (-CH3) on 3-methylpyridine makes it more basic than pyridine H3C 3-methylpyridine 3-bromopyridine Thus, the increasing order of basicity is NH H3C pyrrole Pyridine 3-methylpyridine 3-bromopyridine