Qualitative and Quantitative AnalysishardMCQ SINGLE

Which of the following specific nitrogen-containing organic compounds fails to give a positive LassaQualitative 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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