Why does the presence of a nitro group make the benzene ring less reactive thanthe unsubstituted benzene ring? Explain

The presence of a nitro group makes the benzene ring less reactive than the unsubstituted benzene ring due to the following reasons:

1. Electron Withdrawing Nature: The nitro group (-NO2) is a strong electron-withdrawing group. This means it tends to pull electron density away from the benzene ring towards itself. This reduces the electron density in the benzene ring, making it less likely to participate in reactions that require it to donate electrons.

2. Resonance Effect: The nitro group is also a meta-directing group due to the resonance effect. In the resonance structures of nitrobenzene, the positive charge is located on the carbon atoms of the benzene ring. This makes the benzene ring less nucleophilic and therefore less reactive towards electrophilic aromatic substitution reactions.

3. Deactivation of the Ring: The overall effect of the nitro group is to deactivate the benzene ring. Deactivation refers to the reduction in reactivity of the benzene ring towards electrophilic aromatic substitution, which is the most common reaction of benzene.

In summary, the presence of a nitro group on a benzene ring makes it less reactive due to its electron-withdrawing nature, the resonance effect, and the deactivation of the benzene ring.