In electrophilic aromatic substitution reactions a chlorine substituent
In electrophilic aromatic substitution reactions a chlorine substituent
The correct option is B is a deactivator and an o, p−director
The –I effect of Cl withdraws electron from benzene ring. So,
it tends to destabilize the intermediate carbocation formed during
electrophilic substitution. Conversely, Cl donates it’s lone pair electron to
the aromatic ring and hence increase the electron density at ortho and para
positions.
Thus the lone pair of an electron on the chlorine atom stabilizes
the intermediate carbocation due to resonance. Since, -I effect of Cl is
stronger than it’s +R effect, hence Cl cause net deactivation. Also, further
since +R effect opposes the inductive effect, it makes deactivation less at o,p
positions. Thus, in electrophilic aromatic substitution reactions, a chlorine
substituent is a deactivator and an o,p-director.
Hence, option (b) is correct.
The –I effect of Cl withdraws electron from benzene ring. So, it tends to destabilize the intermediate carbocation formed during electrophilic substitution. Conversely, Cl donates it’s lone pair electron to the aromatic ring and hence increase the electron density at ortho and para positions.
Thus the lone pair of an electron on the chlorine atom stabilizes the intermediate carbocation due to resonance. Since, -I effect of Cl is stronger than it’s +R effect, hence Cl cause net deactivation. Also, further since +R effect opposes the inductive effect, it makes deactivation less at o,p positions. Thus, in electrophilic aromatic substitution reactions, a chlorine substituent is a deactivator and an o,p-director.
Hence, option (b) is correct.
