Explain HVZ (Hell-Volhard-Zelinsky) reaction with equation.

Explanation

b) Carboxylic acids containing `alpha` H - atom on treating with halogens like Chlorine or Bromine in presence of small amount of red phosphorous, the get halogenated at `alpha` - position forming `alpha-` halo carboxylic acids this reaction is known as Hell - Volhard - Zelinsky
`underset("Carboxylic acid")(R-CH_(2)-COOH) overset("1) "X_(2)//"Red P")underset("2) "H_(2)O)rarr underset(alpha - "halocarboxylic licacid")(R-underset(X)underset(|)CH-COOH)`