In the sodium fusion extract test for the detection of sulphur in an organic compound, the addition — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

When an organic compound contains sulphur, sodium fusion creates sodium sulphide ($Na_2S$). Treating the sodium fusion extract with lead acetate yields a black precipitate of lead sulphide ($PbS$), confirming the presence of sulphur: $S^{2-} + Pb^{2+} \rightarrow PbS \downarrow (\text{Black})$.