The correct statement regarding the basicity of arylamines is

A. Arylamines are generally more basic than alkylamines because of aryl group.
B. Arylamines are generally more basic than alkylamines because the nitrogen atom in arylamines is sp hybridised.
C. Arylamines are generally less basic than alkylamines because the lone pair of electrons of nitrogen are delocalised by interaction with the electrons of the aromatic ring.
D. Arylamines are generally more basic than alkylamines because the lone pair of electron of nitrogen are not delocalised by interaction with the z electrons of aromatic ring.
E. Arylamines are generally weaker bases than alkylamines due to electron withdrawing nature shown by aryl group.

Choose the correct answer from the options given below:

C and E only

The correct answer is Option (1) → C and E only

The question revolves around understanding the basicity of arylamines compared to alkylamines, focusing on how the structure and resonance effects of arylamines influence their ability to act as bases.

Basicity in amines \((R-NH_2)\) refers to their ability to donate the lone pair of electrons on the nitrogen atom to accept a proton \((H^+)\). The more readily the lone pair is available, the stronger the base.

Alkylamines: In alkylamines (\(R-NH_2\), where R is an alkyl group), the alkyl groups are electron-donating via the inductive effect. This increases the electron density on nitrogen, making the lone pair more available to accept a proton. Therefore, alkylamines are relatively strong bases.

Arylamines: In arylamines (such as aniline), the nitrogen atom’s lone pair of electrons interacts with the π-electrons of the aromatic ring (through resonance). This delocalization reduces the availability of the lone pair for protonation, which decreases the basicity of arylamines compared to alkylamines.

Resonance Effect in Arylamines
In arylamines, like aniline, the nitrogen atom attached to the aromatic ring has its lone pair partially delocalized into the ring due to resonance. This can be represented as:

This resonance effect leads to the partial withdrawal of electron density from the nitrogen atom, making the lone pair less available to accept a proton. This reduces the basicity of arylamines compared to alkylamines, where no such delocalization occurs.

Statements Analysis

Let us now analyze each statement in the question in light of the above explanation:

Statement A: Arylamines are generally more basic than alkylamines because of the aryl group.

This is incorrect. Arylamines are actually less basic than alkylamines. The aryl group (the benzene ring) in arylamines causes resonance delocalization of the nitrogen's lone pair, making it less available for protonation, thereby reducing basicity.

Statement B: Arylamines are generally more basic than alkylamines because the nitrogen atom in arylamines is sp hybridized.

This is also incorrect. The nitrogen atom in arylamines is sp² hybridized, not sp. In an sp² hybridized nitrogen, the lone pair is in a p-orbital, which overlaps with the π-electron system of the aromatic ring, leading to delocalization and lower basicity. Thus, arylamines are less basic due to this delocalization.

Statement C: Arylamines are generally less basic than alkylamines because the lone pair of electrons of nitrogen are delocalized by interaction with the electrons of the aromatic ring.

This is correct. The key reason for the lower basicity of arylamines compared to alkylamines is the delocalization of the nitrogen’s lone pair into the \(\pi \)-system of the aromatic ring, reducing its ability to accept a proton.

Statement D: Arylamines are generally more basic than alkylamines because the lone pair of electrons of nitrogen are not delocalized by interaction with the \(\pi \) electrons of the aromatic ring.

This is incorrect. The lone pair on nitrogen is delocalized into the \(\pi \)-system of the aromatic ring, and this delocalization is precisely why arylamines are less basic than alkylamines.

Statement E: Arylamines are generally weaker bases than alkylamines due to the electron-withdrawing nature shown by the aryl group.

This is correct. The aryl group exerts an electron-withdrawing effect via resonance. This pulls electron density away from the nitrogen atom, reducing the availability of the lone pair for protonation and making arylamines weaker bases than alkylamines.

Based on the analysis, the correct explanation is:

Statement C is correct because the lone pair of nitrogen in arylamines is delocalized into the aromatic ring, reducing the basicity.

Statement E is correct because the electron-withdrawing nature of the aryl group due to resonance further decreases the basicity of arylamines.

Thus, the correct answer is C and E only