MolSynapsequestion bank
MolSynapse / Question bank / General Organic Chemistry I: Electronic Effects / Applications: stability of carbocations, carbanions, free radicals
JEE Main levelOne or more correct optionsDifficulty 2 of 3g1215

Which of the following statements about the acidity of C-H bonds are correct?

  1. AIsobutane, , is more acidic than methane because its carbanion is tertiary
  2. BCyclopenta-1,3-diene is more acidic than cyclopentane because its conjugate base is aromatic
  3. CThe methyl hydrogens of toluene are more acidic than those of methane
  4. DEthyne is more acidic than ethene because of the higher s-character of its carbon

Answer: B, C, D

Higher s-character, aromaticity of the anion, and resonance delocalisation (benzyl anion) all stabilise the conjugate base and increase acidity. The tert-butyl anion is destabilised by three +I alkyl groups, so isobutane is less acidic than methane.
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