Question

Why resonance doesn't occur in meta positions ?​

Answer 1

Answer:

They increase the electron density inpositions ortho and para to the methyl group making these areas susceptible to attack by electrophiles. And in benzonitrile, the resonancestructures reduce the electron density on the ortho and para positionsmaking the meta position relatively electron rich.

Answer 2

Answer:

Resonance effect only occurs at the ortho and para positions and not at meta positions.

This is because meta positions lack electron density and so electrophiles refuse to attack these positions. The ortho and para positions are electron rich.