Question

Which of the following statement is correct regarding the nature and directive influence of \( \text{NO}_2 \) group in nitrobenzene?

• A. It is an activating group and ortho/para director
• B. It is a deactivating group and ortho/para director
• C. It is a deactivating group and meta director
• D. It is an activating group and meta director

Hint:

Electron-withdrawing groups like \( \text{NO}_2 \) deactivates the ring and direct electrophiles to the meta position.

Answer 1

The Correct Option is C

The question is about identifying the nature and directive influence of the \( \text{NO}_2 \) (nitro) group in nitrobenzene. Let's go step-by-step to analyze the correct statement:

Understanding the Role of Functional Groups:

Functional groups attached to benzene can be classified based on their electronic effects as either activating or deactivating groups and depending on their directive effect as ortho/para directors or meta directors.

• Activating Groups: These groups donate electrons to the benzene ring, stabilizing the intermediate carbocation formed during electrophilic substitution. They are typically ortho/para directors.
• Deactivating Groups: These groups withdraw electrons from the benzene ring, making it less attractive to electrophiles. They are usually meta directors, although with some exceptions (e.g., halogens are deactivating but ortho/para directors due to their lone pairs).

Nature of the \( \text{NO}_2 \) Group:

• The nitro group (\( \text{NO}_2 \)) is strongly electron-withdrawing due to the presence of the highly electronegative oxygen atom and its resonance structures.
• Because of its strong electron-withdrawing nature, \( \text{NO}_2 \) is a deactivating group in electrophilic aromatic substitution reactions.
• It reduces the electron density on the benzene ring, thereby making it less reactive towards electrophiles.

Directive Influence:

• The \( \text{NO}_2 \) group, being electron-withdrawing, stabilizes the negative charge in the intermediate during the reaction at the meta position.
• Therefore, it influences the substitution to occur predominantly at the meta position, making it a meta director.

Conclusion: Based on the electron-withdrawing nature of the \( \text{NO}_2 \) group and its stabilization of the meta position, the correct statement about the \( \text{NO}_2 \) group in nitrobenzene is:

It is a deactivating group and meta director

This matches the provided correct answer.