Test Q: A compound `'X'` was fused with `Na` metal and the extract gave a white precipitate with `AgNO_(3)`. The Lassaigne's extract gave a red colouration with neturl `FeCl_(3)`. Test -R while compound `'Y'` when fused with `Na` methal and subsequent analysis on its Lasaigne's extract did not give any characteristic test. Test -S while compund `Y` on fusion with fusion mixture (sodium carbonate `+` potassium nitrate) `Na_(2)O_(2),` followed by extraction, followed by addition of conc. `HNO_(3)` and ammonium molybdate give a yelow precipitate.
The formula of yellow precipitate is

Options

A. will contain halogens
B. may contain halogens
C. may contain only sulphur
D. will contain only nitrogen

Answer

B

Explanation

Choice b is correct because we cannot be definite about halogens i.e., choice (a) is incorrect because we have not eliminated the presence of `CN^(-)`, for even `AgCN` is white ppt. Hence choices (c) and (d) are incorrect.
The fusion mixture `(KNO_(3)+Na_(2)CO_(3))` on heating undergoes the following reaction.
`KNO_(3)overset(Delta)(to)(KNO_(2)+[O]`
`3Na_(2)CO_(3)|2P+[O]to2Na_(3)PO_(4)+3CO_(2)`
Hence choice (b) is correct while (a), (c) and (d) are incorrect.