Identify the weakest base almong the following.

Step-by-step solution

Phenyl amine (aniline) has a benzene ring attached to the amino group. The lone pair of electrons on the nitrogen atom is delocalized over the benzene ring due to resonance. This delocalization decreases the electron density on the nitrogen atom, making the lone pair less available for protonation. In contrast, ammonia has no such delocalization, and aliphatic amines (iso-propyl amine and n-propyl amine) have electron-donating alkyl groups (+I effect) that increase the electron density on nitrogen, making them stro