Question

Why is resonance more stable than hyperconjugation?

Answer 1

Hint: Resonance and hyperconjugation involve the breaking of the pi and sigma bonded electrons. Sigma bond is comparatively stronger and not easy to break as compared to pi bonds.

Complete Step by Step Solution:
Resonance in chemistry is defined as a method that helps to describe the electrons that have been delocalized in some of the molecules, in which the bonding cannot be expressed by a single Lewis structure.

Hyperconjugation on the other hand is described as the delocalization of the sigma electrons or the lone pair of electrons into the adjacent p-orbital. It is also known as ‘no bond resonance’ or ‘Baker-Nathan effect’.

Hyperconjugation is a type of extension of resonance since both of them help to stabilise the electrons that have been delocalized. Hyperconjugation helps in the delocalization of sigma as well as pi bonded electrons whereas resonance helps in the delocalization of pi bonded electrons only. As the resonance induces delocalization, the total energy of the molecule will decrease when the electron will occupy a high volume, therefore the molecules that undergo the process of resonance are more stable as compared to those molecules which do not.

Note: Hyperconjugation arises from the interaction of the sigma bonded electrons with the nearby pi orbital that is empty or partially filled. This process helps to provide an expanded molecular orbital which therefore increases the stability of the system. The effect of hyperconjugation is stronger when it is compared to the inductive effect in certain molecules.