A. Nitrogen gas
B. NH3
C. CN‾
D. NO
| Test | Observation | Inference |
| Lassaigne’s test for nitrogen | The compound is fused with sodium metal, and the resulting melt is extracted with distilled water. The extract is then tested with ferrous sulfate and then with NaOH and FeSO4. | The appearance of a blue or green coloration with ferrous sulfate indicates the presence of nitrogen. The formation of Prussian blue coloration on adding NaOH and FeSO4 confirms the presence of nitrogen. |
| Lassaigne’s test for sulfur | The compound is fused with sodium metal, and the resulting melt is extracted with distilled water. The extract is then acidified with dilute HCl and then tested with lead acetate. | The formation of a black precipitate of lead sulfide confirms the presence of sulfur. |
| Lassaigne’s test for halogens | The compound is fused with sodium metal, and the resulting melt is extracted with distilled water. The extract is then acidified with dilute nitric acid and tested with silver nitrate. | The formation of a white precipitate of silver halide (AgX) confirms the presence of ha |
Submitted by :- Jamil Ahmed