Which reaction is confirmatory for the presence of Sulfonamide?

The diazo reaction is confirmatory for the presence of sulfonamides due to its ability to produce a colored compound when sulfonamides, which contain an aromatic amine, are present. In the presence of sulfonamides, a diazo reagent reacts with the aromatic amine to form a stable, colored diazo compound. This characteristic reaction allows for the specific identification of sulfonamides in urine or other body fluids, making it a reliable confirmatory test.

In contrast, the other tests listed do not specifically indicate the presence of sulfonamides. The acetone test is used to detect ketone bodies, while Fehling's test is used to assess reducing sugars, particularly glucose. The Biuret test is meant to identify proteins through the presence of peptide bonds. Each of these tests serves a different analytical purpose and is not associated with identifying sulfonamide compounds.