[Sis290025]

On the subject of electron donating groups, is there a significant difference in the (activation) strength between a propyl group and a methyl group (as alkyl groups)? That is, would a propyl group have a greater electron donating inductive effect than an ethyl group?

Thank you for your time.

[moov]

An inductive effect is an electronic effect due to the polarisation of σ bonds within a molecule or ion.
This is typically due to an electronegatvity difference between the atoms at either end of the bond.
The more electronegative atom pulls the electrons in the bond towards itself creating some bond polarity.
In a simple alkyl carbocation, the positive C attracts the electrons in the σ bonds connected to that center towards itself and therefore away from the atom at the other end of the σ bond.

Electrons in C-C bonds are more readily polarised than those in a C-H bond.

Therefore, alkyl groups are better at stabilising C+ than H atoms.
So For +Inductive effect Teriary Carban> secondary-C>Primary-C> hydrogen