Write the reactions involved in the following:
(i) Hell-Volhard Zelinsky reaction
(ii) Decarboxylation reaction

Explanation

(i) Hell-Volhard Zelinsky reaction: Carboxylic acids having `alpha- H` reacts with `Cl_(2)//Br_(2)` in presence of red phosphorus.
`CH_(3) CH_(2) COOH underset((ii) H_(2)O)overset((i) X_(2), "Red P")rarr CH_(3)underset(X)underset(|)(CH) - COOH " " [X = Cl or Br]`
(ii) Decarboxylation reaction
`RCOONa + NaOH underset(630k)overset(CaO)rarr RH + Na_(2) CO_(3)`
or `underset("Sod. acetate")(CH_(3)COONa) + NaOH underset(630k)overset(CaO)rarr underset("Methane")(CH_(4) + Na_(2) CO_(3))`