Chemistry - Salt Analysis Question with Solution | TestHub
On reacting an aqueous salt A with H₂S in an acidic medium, a brownish-black precipitate (B) is formed. This precipitate is not soluble in YAS, but upon treatment with dilute HNO₃, it dissolves and forms a white precipitate (D) with the evolution of a gas C.
white ppt. is :-
Options:
Answer:
Solution:
The brownish-black precipitate (B) is a Group IIA metal sulfide (like CuS or PbS) that is insoluble in Yellow Ammonium Sulfide (YAS). Dilute HNO₃ acts as an oxidizing agent, reacting with the sulfide to produce a metal nitrate and elemental Sulfur (S). This elemental sulfur is the white precipitate (D) mentioned, which typically appears as a milky white turbidity in the solution. The gas (C) evolved during this oxidation-reduction process is Nitric Oxide (NO). Therefore, the correct option is (B) S.