Lassaigne's Test
In Lassaigne's test for nitrogen, formation of Prussian blue color after treatment with FeSO4 and acidification indicates presence of:
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About This Question
- Subject
- chemistry
- Chapter
- purification and characterisation of organic compounds
- Topic
- lassaigne's test
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
Nitrogen only
During sodium fusion, nitrogen in the organic compound is converted to sodium cyanide. This reacts with Fe2+ to form ferrocyanide, which on oxidation/acidification gives ferric ferrocyanide (Prussian blue). Hence blue color indicates nitrogen in the original compound.
This medium difficulty chemistry question is from the chapter purification and characterisation of organic compounds, covering the topic of lassaigne's test. It appeared in the 2025 exam.
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