Question

Which of the following compounds will give the Hell-Volhard-Zelinsky reaction?

• A. R-CH$_2$-COOH
• B. R$_3$C-CHO
• C. R$_2$CO
• D. H-COOH

Answer 1

The Correct Option is A

The Hell-Volhard-Zelinsky reaction involves the halogenation of carboxylic acids possessing at least one α-hydrogen atom. The presence of an α-hydrogen adjacent to the carboxylic acid group (-COOH) is a prerequisite for this reaction.

Evaluation of each option is as follows:

• R-CH₂-COOH: This compound, a carboxylic acid, possesses an α-hydrogen (on the carbon adjacent to the carbonyl). Thus, it is amenable to the Hell-Volhard-Zelinsky reaction.
• R₃C-CHO: This molecule is an aldehyde, not a carboxylic acid. It lacks the requisite α-hydrogen adjacent to a carboxylic acid group, disqualifying it from this reaction.
• R₂CO: This compound is a ketone, similarly lacking the essential α-hydrogen adjacent to a carboxylic acid functional group.
• H-COOH: Formic acid is devoid of any α-hydrogen atom next to its carboxyl group, precluding its participation in the Hell-Volhard-Zelinsky reaction.

Consequently, R-CH₂-COOH is identified as the correct answer due to its compliance with the requirements for the Hell-Volhard-Zelinsky reaction.