Answer to Question #124711 in Organic Chemistry for Laiba

Question

Reactivity of substituted benzene towardselectrophile

Answer 1

Reactivity of substituted benzene towards electrophile: Substituent groups on a benzene ring affect aromatic electrophilic substitution reactions in two ways: Increase or decrease the reactivity of the benzene ring.

If the substituent (+I or +R group) donates (releases) electrons to the benzene ring then the electron density of the ring will increase, resulting the activation of ring. Therefore, the reaction rate is increased relative to the rate on an unsubstituted benzene ring.

If the substituent (-I or -R group) withdrawing electrons from the benzene ring then the electron density of the ring will decrease, resulting in deactivation the ring. Therefore, the reaction rate is decreased relative to the rate on an unsubstituted benzene ring.