(i), (ii) 2-hexanone undergoes haloform reaction to form bromoform and a carboxylate ion. This carboxylate ion undergoes hydrolysis to give pentanoic acid. CH3CH22-hexanoneCH2H2CO∥C−CH3(i)NaOBr
(iii), (iv) Pentanoic acid, react with bromine in presence of red-phosphorus to give α-bromocarboxylic acid. This reaction is Hell-Volhard-Zelinsky reaction.
CH3CH2CH2CH2COOH(iii) Red P.Br2(iv) H2OCH3CH2H2CBr∣H−COOH