Which from following compounds has lowest pK _ b value?

Step-by-step solution

Determining which compound has the lowest pK _ b value requires identifying the strongest base. A lower pK _ b corresponds to greater base strength. Analyzing the compounds: Benzenamine is an aromatic amine where the nitrogen lone pair is resonance-delocalized into the ring, drastically reducing basicity and placing it as the weakest base. Ammonia serves as the reference base. Aliphatic amines, like propan-2-amine and N-ethylethanamine, are stronger bases than ammonia due to the electron-donating inductive effect o