Question:
The amine with the highest $pK_{b}$ value is ________.
The amine with the highest $pK_{b}$ value is ________.
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Lower $pK_b$ = Stronger base; Resonance with ring = Weaker base.
Updated On: Jun 26, 2026
- Methanamine
- N-methylmethanamine
- Benzeneamine
- N-Methylaniline
- Ethanamine
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The Correct Option is C
Solution and Explanation
Step 1: Concept
A higher $pK_b$ value indicates a weaker base.
Step 2: Meaning
Basicity of amines depends on the availability of the lone pair on the Nitrogen atom.
Step 3: Analysis
In Benzeneamine (aniline), the lone pair is delocalized into the benzene ring by resonance, making it significantly less available for donation.
Step 4: Conclusion
Aliphatic amines (like methanamine) are much stronger bases than aromatic amines. Benzeneamine is the weakest base here and thus has the highest $pK_b$. Final Answer: (C)
A higher $pK_b$ value indicates a weaker base.
Step 2: Meaning
Basicity of amines depends on the availability of the lone pair on the Nitrogen atom.
Step 3: Analysis
In Benzeneamine (aniline), the lone pair is delocalized into the benzene ring by resonance, making it significantly less available for donation.
Step 4: Conclusion
Aliphatic amines (like methanamine) are much stronger bases than aromatic amines. Benzeneamine is the weakest base here and thus has the highest $pK_b$. Final Answer: (C)
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