A forensic chemist uses 2,4-dinitrophenylhydrazine to detect the presence of a carbonyl group in an unknown sample. What observation indicates a positive result?
Q1. A forensic chemist uses 2,4-dinitrophenylhydrazine to detect the presence of a carbonyl group in an unknown sample. What observation indicates a positive result?
Answer: Orange-red precipitate
Explanation: 2,4-DNPH (Brady's reagent) forms a yellow or orange-red precipitate with carbonyls. A silver mirror is specific to aldehydes, not all carbonyls.