Fundamentals of Organic ChemistryChemistryAmines
Which of the following statements is true regarding the relative basic character of pyridine and pyrrole?
Options
- APyridine is less basic because it is a tertiary amine.
- BBoth are equally basic.
- CPyridine is more basic because its non-bonding electron pair is not a part of the aromatic sextet.
- DPyrrole is more basic because its non-bonding electron pair occupies an sp ³ orbital.
Correct answer
C. Pyridine is more basic because its non-bonding electron pair is not a part of the aromatic sextet.
Step-by-step solution
In pyridine, the nitrogen atom is sp^2 hybridized and its lone pair of electrons is present in an sp^2 hybridized orbital. This non-bonding electron pair lies in the plane of the ring and does not participate in the delocalized electron system of the aromatic ring. Therefore, the lone pair is readily available for protonation, making pyridine a base. In pyrrole, the nitrogen atom is also sp^2 hybridized, but its lone pair of electrons resides in an unhybridized p orbital. This lone pair participates in the continuo