aromatic amine basicity

Question

Aniline is less basic than methylamine due to:

RankGuru · Accepted Answer

1. **Definition**: Basicity depends on the availability of the lone pair of electrons on the Nitrogen atom.
2. **Methylamine**: The methyl group increases electron density on Nitrogen via the $+I$ effect.
3. **Aniline**: The lone pair on Nitrogen is in conjugation with the $\pi$-electrons of the benzene ring.
4. **Mechanism**: Through **resonance**, the lone pair is delocalized into the ortho and para positions of the ring.
5. **Consequence**: The electrons are 'busy' within the ring and are less available for protonation. Additionally, the anilinium ion ($C_6H_5NH_3^+$) lacks resonance stabilization, making it less stable compared to the parent aniline.

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aromatic amine basicity

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