Our teacher told us that the inductive effect or the electron displacement effect can only affect the sigma electrons. I did not understand why this should be.
I reasoned it can not affect the pi electrons, because they are "delocalized".
Also, for measuring the displacement, the C-H bond is taken as a reference. The C-H bond does not have a pi bond, and so we can not consider pi electrons as being affected
Is it true that the inductive effect or the electron displacement effect affects only sigma electrons? Why should it be so?
I am not asking if it operates through single bonds only, as asked in this question.