Why must Lassaigne's extract be strictly boiled with concentrated before testing for halogens with ? — Practical Organic Chemistry and Purification Chemistry Question

💡 Solution & Explanation

Boiling with $HNO_3$ expels $HCN$ and $H_2S$ gases. If left in solution, cyanide and sulphide ions would falsely precipitate as white $AgCN$ and black $Ag_2S$.