Among the following amines, the strongest Brönsted base is __________.
Option (iv) is the correct answer.
Explanation: is a stronger base than aniline because of the delocalisation of the lone pair of electrons at N-atom and into the Benzene Ring. And in Pyrrole, as the lone pair electrons on N-atom donate to aromatic sextet formation, it is not basic at all. Hence, Pyrrolidine accepts the proton readily while also being the strongest base.