Basicity of compounds

In chemistry, the term "basicity" refers to the ability of a compound to donate a pair of electrons or accept a proton. A basic compound is one that can accept a proton and forms a conjugate acid. The basicity of a compound depends on the presence of electron-donating groups or atoms.

Comparing the compounds

To determine the most basic compound among the options given, let's compare their structures and identify any electron-donating groups or atoms.

a) Acetanilide:
Acetanilide is an organic compound that consists of an acetamide group attached to an aniline group. The aniline group contains a nitrogen atom, which can act as a lone pair donor. However, the presence of the acetyl group (-COCH3) attached to the nitrogen atom decreases its basicity. The acetyl group is an electron-withdrawing group, which decreases the availability of the lone pair of electrons on the nitrogen atom.

b) Benzylamine:
Benzylamine is an organic compound that consists of a benzyl group attached to an amino group (-NH2). The amino group contains a lone pair of electrons, which can act as a donor. The benzyl group is a relatively weak electron-donating group, but it does not significantly decrease the basicity of the amino group. Therefore, benzylamine is more basic than acetanilide.

c) p-Nitroaniline:
p-Nitroaniline is an organic compound that consists of an aniline group with a nitro group (-NO2) attached to the para position of the benzene ring. The nitro group is an electron-withdrawing group, which decreases the basicity of the amino group. Therefore, p-nitroaniline is less basic than both acetanilide and benzylamine.

d) Aniline:
Aniline is the simplest compound among the options given. It consists of a benzene ring attached to an amino group (-NH2). The amino group contains a lone pair of electrons, making aniline a basic compound. However, benzylamine is more basic than aniline because the benzyl group is a stronger electron-donating group than the phenyl group.

Conclusion

Among the given options, the most basic compound is benzylamine (option b). It has a relatively strong electron-donating group (benzyl group) attached to the amino group, which increases its basicity compared to the other compounds.