Question

Which of the following is ortho/para directing and deactivating group?

• A. $-F$
• B. $-Cl$
• C. $-Br$
• D. All of the above

Answer 1

The correct option is D All of the above

Halogen group (-X) has two effects
(i) Negative inductive effect (-I)
(ii) Positive resonance effect (+R)

Due to -I effect, it attract the electron toward itself and reduce the electron density on benzene so it deactivates the ring and the substitution takes place at meta position.

Due to +R effect, it increase the electron density at ortho and para position by delocalisation of electrons. Resonance effect dominates over inductive effect.

Hence, in halobenzene substitution takes place at ortho and para position.