In 2nd plz explain how these two effects control orientation and reactivity

Asked by lovemaan5500 | 13th Jan, 2020, 09:36: PM

Expert Answer:

  • Chlorine withdraws electrons through inductive effect and releases electrons through resonance.

 

  • Through inductive effect, chlorine destabilises the intermediate carbocation formed during the electrophilic substitution.

 

  • Through resonance, halogen tends to stabilise the carbocation and the effect is more pronounced at ortho- and para- positions.
  • The inductive effect is stronger than resonance and causes net electron withdrawal and thus causes net deactivation.
  • The resonance effect tends to oppose the inductive effect for the attack at ortho- and para positions and hence makes the deactivation less for ortho- and para attack.
  • Reactivity is thus controlled by the stronger inductive effect and orientation is controlled by resonance effect.

 

         

Answered by Ramandeep | 15th Jan, 2020, 10:55: AM