Which of the following compound will not undergo azo coupling reaction with benzene diazonium chloride? 

Nitrobenzene 

The correct answer is option 4. Nitrobenzene.

Azo coupling is a reaction between a diazonium salt and an aromatic compound containing an activated ortho- or para-position. In this reaction, the diazonium salt acts as the electrophile, while the aromatic compound serves as the nucleophile. The result is the formation of an azo compound, characterized by the presence of a nitrogen-nitrogen double bond \((-N=N-)\) connecting two aromatic rings.

Let us break down why nitrobenzene will not undergo azo coupling reaction with benzene diazonium chloride:

Nitrobenzene Structure: Nitrobenzene is benzene with a nitro \((-NO_2)\) group attached to it. The nitro group is a strong electron-withdrawing group due to its electronegative oxygen and nitrogen atoms, which withdraw electron density from the benzene ring via inductive and resonance effects.

Effect on Benzene Ring: The presence of the nitro group deactivates the benzene ring towards electrophilic aromatic substitution reactions. This deactivation arises from the withdrawal of electron density from the benzene ring, making it less reactive towards electrophiles.

Lack of Activated Positions: Due to the deactivating nature of the nitro group, the ortho and para positions of nitrobenzene are not activated towards electrophilic substitution reactions. In fact, the ortho and para positions are strongly deactivated by the nitro group.

Azo Coupling Requirement: Azo coupling reactions require an aromatic compound with activated ortho- or para-positions to facilitate the coupling with the diazonium salt. Since nitrobenzene does not have activated ortho- or para-positions, it cannot undergo azo coupling with benzene diazonium chloride.

In contrast, compounds like aniline, phenol, and anisole contain activating groups (such as amino, hydroxy, or methoxy groups) that activate the ortho- or para-positions towards electrophilic aromatic substitution reactions. Therefore, they are capable of undergoing azo coupling with benzene diazonium chloride.

In summary, nitrobenzene's lack of activated ortho- or para-positions due to the strong deactivating effect of the nitro group prevents it from undergoing azo coupling reaction with benzene diazonium chloride.