Question

why ayl group shows - inductive effect?

Answer 1

As we know that functional groups containing double bonds like C=C or C=O have sp² hybridised carbons which pull the electron pair of adjacent single bonds towards itself and thus show -I effect.

Similarly, incase of aryl group the benzene ring is sp² hybridized and posesses high electron density due to aromatic nature, thus leads to the -I effect.