Problem 114 - A Complete Resource Book in Chemistry for JEE Main

Question

The refluxing of the silver salt of the carboxylic acid in \(\mathrm{CCl}_{4}\) to form haloalkane or haloarene is called (a) Friedel-Crafts reaction (b) Wittig reaction (c) Hoffmann's bromamide reaction (d) Hunsdiecker reaction

Step-by-Step Solution

Answer

(d) Hunsdiecker reaction

Step 1: Analyze the Reaction Conditions

Given the problem, we focus on the refluxing of the silver salt of a carboxylic acid in carbon tetrachloride ( CCl_4 ), which needs to be associated with a particular named reaction that results in the formation of haloalkanes or haloarenes.

Step 2: Identify the Named Reaction

The reaction involving silver salt of the carboxylic acid with halogen (often in solvent like CCl_4 ) is known as the Hunsdiecker reaction. This reaction specifically results in the formation of haloalkanes or haloarenes by the decarboxylation of the carboxylic acid.

Step 3: Confirm with Options Provided

We need to ensure that one of the answer options matches the Hunsdiecker reaction. Among the options provided: Friedel-Crafts, Wittig, Hoffmann's bromamide, and Hunsdiecker reaction, only the Hunsdiecker reaction aligns perfectly with the reaction described.

Key Concepts

Named Reactions

Understanding named reactions is crucial in the study of organic chemistry as they often involve unique mechanisms or significant transformations that have been named after the chemists who discovered them. One such reaction is the Hunsdiecker Reaction. This named reaction involves the decarboxylation of the silver salt of a carboxylic acid in the presence of a halogen. Specifically, in this context, carbon tetrachloride (\( \mathrm{CCl}_{4} \)) is used as the solvent. Named reactions like this are taught to help recognize the conditions that lead to specific organic transformations. This recognition is key in approaching organic synthesis problems.Named reactions provide a shorthand way to describe transformations without having to detail every step, which is particularly helpful in contexts like academic exercises or rapid synthesis planning. By associating a particular set of reagents and conditions with a named reaction like the Hunsdiecker, students can more easily predict the outcome of that reaction.

Carboxylic Acid Derivatives

Carboxylic acid derivatives are organic compounds that can be viewed as having been derived from carboxylic acids. These derivatives include esters, amides, anhydrides, and in our case, silver salts of carboxylic acids. Silver salts are crucial in the Hunsdiecker Reaction. These salts are formed when a carboxylic acid reacts with a silver ion. In the context of the Hunsdiecker Reaction, these silver salts are key because they facilitate the removal of the carboxyl group as carbon dioxide. Carboxylic acid derivatives are versatile in organic synthesis due to their variety and reactivity. They provide various pathways for transformations which can lead to a broad range of products. By identifying and understanding these derivatives, students gain insight into how changes in structure can lead to different chemical behavior and reactivity, as seen in the mechanism of the Hunsdiecker Reaction.

Decarboxylation

Decarboxylation is an important chemical reaction and a common theme in organic chemistry, particularly when dealing with carboxylic acids or their derivatives. In simple terms, decarboxylation involves the removal of a carboxyl group from a molecule, releasing it as carbon dioxide (\( \mathrm{CO}_{2} \)). In the context of the Hunsdiecker Reaction, decarboxylation occurs when the silver salt of a carboxylic acid reacts with halogen. This releases carbon dioxide and forms a haloalkane or haloarene.This reaction is essential not only in the Hunsdiecker Reaction but also in many biochemical processes. Understanding decarboxylation helps students grasp how certain transformations occur, which is fundamental in both laboratory synthesis and in broader contexts such as metabolic pathways where enzymes catalyze similar processes. Recognizing the conditions under which decarboxylation occurs, such as the presence of heat or specific reagents, is vital in predicting reaction outcomes.