explain effect of resonance on aromatic electrophilic substitution with suitable example in organic chemistry?

Answer 1

more resonance structures that are possible the more stable a given structure is. all you do is push electrons and you have charged resonance structres as well (just not as important). You need your intermediate to be moderately stable so resonance is a big thing.

Answer 2

For the meta question, i do not see any activation or deactivation by resonance platforms. For the ortho-para resonance platforms, the non-bonded electrons of the phenol will turn on the ortho and para positions. you should be able to entice resonance platforms with a unfavourable charge on the fragrant ring (o/p) and a favorable charge on the oxygen.