Question

In Hunsdiecker reaction, the alkyl bromide contains one carbon less than those in_______
A. Carboxylic acid
B. Oxalic acid
C. Hypohalite
D. None of these

Answer 1

Hint- The silver(I) salts of carboxylic acids respond with halogens to give shaky intermediates which promptly decarboxylate thermally to yield alkyl halides. The reaction is accepted to include homolysis of the C-C bond and a radical chain mechanism.

Complete answer:
The hunsdiecker reaction is a name reaction in organic chemistry where silver salts of carboxylic acids respond with a halogen (ordinarily bromine molecules) to create an organic halide (or organic bromide). It is a case of both a decarboxylation and a halogenation reaction as the product has one less carbon atom than the beginning material (lost as carbon dioxide) and a halogen atom is presented in its place.
The mechanism of the hunsdiecker reaction is-
The reaction involves a radical chain mechanism.
Initiation:
The bromine reacts with the silver carboxylate to give an unstable acyl hypobromite.
$RCO{O^ - }A{g^ + } + B{r_2} \to RCOO - Br + AgBr$
The weak O-Br bond undergoes homolytic cleavage to form an acyl radical.
$RCOO - Br \to RCOO. + .Br$
Propagation:
The acyl radical loses a molecule of $CO_2$ to form an alkyl radical.
$RCOO. \to R. + C{O_2}$
The alkyl radical reacts with the acyl hypobromite to form an alkyl bromide and generate another acyl radical.
$R. + RCOO - Br \to R - Br + RCOO.$
From the definition of this name reaction it is clear that carboxylic acid is the correct option.
Thus, option A is the correct option.

Note: In 1861, Russian physicist Alexander Borodin arranged methyl bromide from silver acetate in a consolidated decarboxylation and halogenation reaction. Expanding on this work, in 1939 German scientific experts Cläre and Heinz Hunsdiecker showed that when silver salts of carboxylic acids respond with a halogen, an alkyl halide is shaped which has one less carbon atom than the substrate. Hence this reaction got known as the Hunsdiecker reaction or in some cases the Hunsdiecker–Borodin reaction, referencing Borodin's previous work.