Identify the product in the following sequence: \(3,4,5\) -Tribromoaniline \(\frac{\text { (i) diazotization }}{\text { (ii) } \mathrm{H}_{3} \mathrm{PO}_{2}}\) ? (a) \(3,4,5\) - Tribromobenzene (b) 3, 4, 5-Tribromonitrobenzene (c) \(2,4,6\) - Tribromobenzene (d) \(1,2,3\) -Tribromobenzene

Tribromoaniline is a derivative of aniline where three bromine atoms are substituted on the benzene ring. In the context of organic chemistry, it's important to note the positions of these bromine atoms, as they are key in determining the properties and reactivity of the molecule. For 3,4,5-tribromoaniline, the bromine atoms are located at the third, fourth, and fifth positions of the benzene ring, which influences how this compound undergoes further chemical reactions.

Due to the presence of the bromine atoms, which are electron-withdrawing groups, the electron density of the benzene ring is decreased. This makes the amine group, which is an electron-donating group, less reactive towards certain types of electrophilic substitution reactions. However, this configuration allows for other chemical transformations, as seen in the diazotization process followed by reduction.

Diazonium salt formation is a critical intermediate step in many organic syntheses. It forms when a primary aromatic amine, such as aniline or substituted anilines like tribromoaniline, is treated with nitrous acid, which is usually generated in situ from sodium nitrite and a strong acid like hydrochloric acid. The reaction takes place under cold conditions to prevent the decomposition of the diazonium group.

The resulting diazonium salt is a versatile intermediate that can be used to produce a variety of different functional groups. In the case of our exercise, the diazonium intermediate is unstable and not isolated; instead, it's directly subjected to further reactions. Understanding the delicate nature and reactivity of diazonium salts is important for predicting the outcome of reactions they're involved in.

Hypophosphorous acid (H3PO2) is known for its reducing properties, especially in the context of aromatic diazonium salts. Its use in the reduction process converts the diazonium ion into a hydrogen, effectively removing the nitrogen and forming a new compound in the process. This reduction step is crucial for transforming an amine group into a hydrogen atom on the benzene ring, which can significantly alter the chemical behavior of the compound.

Moreover, the reduction doesn't affect the substituents that are already present on the ring, such as the bromine atoms in tribromoaniline. Therefore, understanding the selective nature of hypophosphorous acid reduction allows us to accurately predict the structure of the final product in reactions where it's applied.

The conversion of an aromatic amine into other functional groups is a common transformation in organic chemistry. This can be achieved through various reactions, one of which involves diazotization followed by reduction. In our exercise, the primary aromatic amine — tribromoaniline — is converted to a different compound through these two specific steps.

Initially, the amine group is converted into a diazonium salt, which is a high-energy intermediate. Subsequently, the application of hypophosphorous acid reduction removes the diazonium group and replaces it with a hydrogen atom. The outcome is a halogenated benzene where the halides are preserved in their original positions, and the amine has been converted to a hydrogen, leading to a simpler structure. This methodology is key to synthesizing various derivatives from aromatic amines.