Question

Explain HVZ reaction of carboxylic acids
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Answer 1

Explanation:

Mechanism of the Hell-Volhard-Zelinsky Reaction. Phosphorus reacts with bromine to give phosphorus tribromide, and in the first step this converts the carboxylic acid into an acyl bromide. An acyl bromide can readily exist in the enol form, and this tautomer is rapidly brominated at the α-carbon.

Answer 2

Treatment with bromide and catalytic amounts of phosphorus leads to a selective bromination of carboxylic acid.
Inteally red phosphorus and bromide will react each other to give PBR 3..