MolSynapsequestion bank
MolSynapse / Question bank / General Organic Chemistry I: Electronic Effects / Aromatic, antiaromatic and non-aromatic rings
JEE Advanced levelOne or more correct optionsDifficulty 3 of 3g1248

Select all correct statements about the compound shown.

  1. AThe nitrogen lone pair lies in the ring plane and is not part of the pi sextet
  2. BThe ring has 6 pi electrons
  3. CProtonation on nitrogen does not destroy the aromatic sextet
  4. DThe nitrogen lone pair contributes two electrons to the aromatic sextet

Answer: A, B, C

The compound shown is pyridine. Its nitrogen lone pair lies in an sp2 orbital in the ring plane, so it is not part of the sextet (A true). The sextet comes from three C=C/C=N bonds, i.e. 6 pi electrons (B true). Because the lone pair is not used by the pi system, protonation leaves the aromatic sextet intact (C true). The nitrogen is sp2, not sp3, and its lone pair does not enter the sextet (D false).
Practice General Organic Chemistry I: Electronic Effects More on Aromatic, antiaromatic and non-aromatic rings
Previous questionNext question

More questions on Aromatic, antiaromatic and non-aromatic rings