Which of the following specific nitrogen-containing organic compounds fails to give a positive Lassa — Qualitative and Quantitative Analysis Chemistry Question
Question
Which of the following specific nitrogen-containing organic compounds fails to give a positive Lassaigne's test for nitrogen because it lacks a fundamental elemental prerequisite for the formation of the sodium fusion extract intermediate?
Answer: C
💡 Solution & Explanation
The Lassaigne's test for nitrogen detects the presence of the cyanide ion ($CN^-$) in the sodium fusion extract. To form $NaCN$, the organic compound must contain both Nitrogen and Carbon. Hydrazine ($NH_2NH_2$) lacks carbon entirely. Thus, it cannot form $NaCN$ upon fusion with sodium, and subsequently fails to produce the Prussian blue color.
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