Question

Why halogens are ortho para directing but deactivating group?

Answer 1

generally elctron donating groups are ortho-para directing groups whereas electron withdrawing froups are meta directing.electron donating groups have lone pairs of electrons that ae shared with the aromatic rings. hence halogens are ortho para directing groups.


Again halogens bonded to aromatic ring forms three lone pairs of electrons. Thus may cause resonance in the ring.afain halogens are highly electro negative and hence these are -I effect.hence halogens are deactivating groups