Question

Which is stronger Hyperconjuction or Inductive effect?

Answer 1

Hyperconjugation:

• It includes the $\mathrm{C}-\mathrm{H}$ sigma ($\mathrm{\sigma }$) electrons delocalization (partial conjugation) of an alkyl group that is directly attached to an atom of an unsaturated system or to an atom with an unshared p orbital.
• The hyperconjugation interaction and cation stabilization increase as the number of alkyl groups increases which are attached to the positively charged carbon atom.
• For example, Ethyl cation (${\mathrm{CH}}_3\stackrel{+}{{\mathrm{CH}}_2}$) has an electron that can then be delocalized from a C-H bond associated with this empty p orbital into this empty p orbital when one of the C-H bonds of the methyl group aligns in this plane.

Inductive effect:

• The formation of a covalent bond between the atoms of different electronegativity than the electron density is high towards the high electronegative atom of the bond.
• The shifting of electron density results in a polar covalent bond that leads to various electronic effects in the compounds.
• The inductive effect is the ability of substituents either by electron withdrawn and electron donate density to the attached Carbon atom.
• For example, there is a polar covalent bond between Carbon and Chlorine in the Chloroethane (${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Cl}$) that create a partial positive charge (${\mathrm{\delta }}^{+}$) on the carbon atom and a partial negative charge (${\mathrm{\delta }}^{-}$) on the Chlorine. The development of some partial positive charge (${\mathrm{\delta \delta }}^{+}$) on the second Carbon atom. The shift of electron density from the second Carbon atom to the partial negative end of the polar bond. A polar Carbon-Chlorine bond induces polarity in the adjacent bonds by polarizing the adjacent sigma bond.
• Stronger between hyperconjugation and inductive effect: Hyperconjugation is stronger than the inductive effect because of the permanent effect.
• In the case of an inductive effect, the electron density in a bond between unlike atoms is not uniform, but in the case of hyperconjugation, the electron density is uniform.
• The interaction between sigma and pi bonds occurs in hyperconjugation, but the inductive effect is caused by the polarization of sigma bonds.