GOC 3

Question 1

Why does the presence of nitrogroup make the benzene ring less reactive in comparison to other unsubstituted benzene ring. Explain.

Answer 1

The overall e- density of benzene ring decreases due to strong -I effect of nitro group in nitrobenzene making further substitution difficult.

Question 2

In an electrophilic substitution reaction of nitrobenzene how the presence of nitrobenzene affect the reaction?

Answer 2

Nitro group by the virtue of strong inductive effect withdraws electrons from the ring and increases the charge and destabilizes the carbocation.
As Nitro Group is electron withdrawing by nature it decreases the stability of such product and hence meter attack is more feasible when electron withdrawing substitutes are attached.

Question 3

For an electrophilic substitution reaction how the presence of halogen atom in the benzene ring affect the reaction.

Answer 3

Four and electrophilic substitution reaction, the presence of halogen atom in the Belcene Ring Deactivates ring by inductive effect and increases the charge d.ensity at Ortho and para positions relative to meter position by resonance.
When chlorine is attached to benzene ring chlorine being more electronegative pulls the electron because of its I effect the electron cloud of benzene becomes less dense thus chlorine makes benching ring in array halide somewhat deactivated. But due to resonance, the electron density on ortho and para positions is greater than on meta position hence halogens are orthopara directing.