Question

Identify the resonance-stabilized carbocation among the given options.

• A. A six-membered ring containing a nitrogen atom and a positive charge on a carbon atom adjacent to the nitrogen, with a double bond in conjugation.
• B. A six-membered ring with a nitrogen atom and a positive charge on a carbon atom not adjacent to the nitrogen, with a double bond not in conjugation.
• C. A four-membered ring with a positive charge on a carbon atom.
• D. A linear chain of four carbon atoms with a positive charge on the terminal carbon.

Answer 1

Answer: (A)

A six-membered ring containing a nitrogen atom and a positive charge on a carbon atom adjacent to the nitrogen, with a double bond in conjugation.

Answer 2

The first option describes a structure where a positive charge is adjacent to a nitrogen atom and conjugated with a double bond. This arrangement allows for significant resonance stabilization, as the positive charge can be delocalized through the pi system and onto the lone pair of electrons on the nitrogen. Such delocalization spreads the charge over a larger area, increasing the stability of the carbocation.