MolSynapsequestion bank
MolSynapse / Question bank / General Organic Chemistry I: Electronic Effects / Applications: stability of carbocations, carbanions, free radicals
JEE Main levelSingle correct optionDifficulty 2 of 3g1204

Which of the following carbanions is the most stable?

  1. Acyclopenta-2,4-dien-1-ide (cyclopentadienyl anion)
  2. Bcycloprop-2-en-1-ide (cyclopropenyl anion)
  3. Ccyclopentyl anion
  4. Dcyclohexyl anion

Answer: A

The cyclopentadienyl anion is planar, cyclic and fully conjugated with 6 pi electrons, so it is aromatic and very stable. The cyclopropenyl anion has 4 pi electrons (antiaromatic), and the cyclopentyl and cyclohexyl anions are simple secondary alkyl carbanions.
Practice General Organic Chemistry I: Electronic Effects More on Applications: stability of carbocations, carbanions, free radicals
Previous questionNext question

More questions on Applications: stability of carbocations, carbanions, free radicals