Question

When propanoic acid is treated with bromine and red phosphorus in aqueous medium, 2-bromopropanoic acid is formed. This reaction is known as

• A. Kolbe reaction
• B. Wurtz reaction
• C. Hell-Volhard-Zelinsky reaction
• D. Etard reaction
• E. Wurtz-Fittig reaction

Hint:

The Hell-Volhard-Zelinsky reaction is useful for introducing bromine at the alpha position of carboxylic acids, often used in synthesis of more complex molecules.

Answer 1

The Correct Option is C

Step 1: The Hell-Volhard-Zelinsky reaction specifically involves the halogenation of the alpha-carbon of carboxylic acids. 
Step 2: This reaction uses a halogen (Br\(_2\)) and red phosphorus, which generates phosphorus tribromide (PBr\(_3\)), acting as a catalyst. 
Step 3: Phosphorus tribromide converts the carboxylic acid to an acyl bromide, which subsequently undergoes alpha-bromination. 
Step 4: The product, 2-bromopropanoic acid, confirms the pathway and mechanism of the Hell-Volhard-Zelinsky reaction.