In Lassaigne's test for identifying halogens, it is chemically mandatory that the sodium fusion extr — Qualitative and Quantitative Analysis Chemistry Question
Question
In Lassaigne's test for identifying halogens, it is chemically mandatory that the sodium fusion extract be boiled vigorously with concentrated $HNO_3$ before the addition of $AgNO_3$. The primary scientific rationale for this procedural step is to:
Answer: C
💡 Solution & Explanation
If the organic compound also contains nitrogen or sulphur, fusion creates $NaCN$ and $Na_2S$. These ions interfere by forming $AgCN$ (white ppt) and $Ag_2S$ (black ppt) with $AgNO_3$. Boiling with $HNO_3$ decomposes them into volatile $HCN$ and $H_2S$ gases.
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