Question

Hunsdiecker reaction is an example of:
A. addition reaction
B. halogenation reaction
C. substitution action
D. all of the above.

Answer 1

Hint: In the Hunsdiecker reaction, a type of reaction takes place where the halogen like bromine gets attached to the silver salt of carboxylic acid. After that, decarboxylation takes place and the desired product is obtained.

Complete step by step answer:
In order to answer our question, we need to know about different types of reactions. In addition to reaction, the element or atom simply gets added and no other side product is formed along with it. Alkenes react with hydrogen upon heating in the presence of a suitable catalyst to form the corresponding alkanes. This reaction is called catalytic hydrogenation. Alkenes react with halogen acids to form mono haloalkanes also called alkyl halides.
In a substitution reaction, one or more hydrogen atoms in the alkane molecule are replaced by suitable atoms or groups called substituents. There is no change in the arrangement of the carbon atoms or in the carbon atom skeleton.
Halogenation reaction is a part of substitution reaction, as the halogens get substituted in place of hydrogen. The types of halogenation reactions are:
i.Chlorination
ii. Bromination
iii. Iodonation
iv. Fluorination
The Hunsdiecker reaction involves silver salts of carboxylic acid to react with halogens, which lead to alkyl halides, on decarboxylation.
\[C{{H}_{3}}C{{H}_{2}}COOAg+B{{r}_{2}}\xrightarrow{CC{{l}_{4}}}C{{H}_{3}}C{{H}_{2}}Br+C{{O}_{2}}+AgBr\]
This reaction can be also said as a halogenation reaction, although it is decarboxylation.

So, our correct answer is option B.

In halogenation reaction, a free halogen radical is made to attack on the respective reagent, it is completed in mainly three steps, mainly chain initiation, chain propagation and chain termination.

Note: The iodination of alkanes is of reversible nature because H-I formed in the reaction can easily combine with iodoalkane to form alkane and iodine again. Since fluorine is the most reactive halogen, its reaction with alkanes will lead to the breaking C-C as well as C-H bonds. No fluorinated product will be formed.