In qualitative analysis when H_2S is passed through an aqueous solution of salt acidified with dil. HCl, a black precipitate is obtained. On boiling the precipitate with dil. HNO_3, it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives .............

In qualitative analysis when H_2S is passed through an aqueous solutio

1.	In qualitative analysis when H_2S is passed through an aqueous solution of salt acidified with dil. HCl, a black precipitate is obtained. On boiling the precipitate with dil. HNO_3, it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives .............
Answer» Deep blue PRECIPITATE of `CU(OH)_2` Deep blue solution of `[Cu(NH_3)_4]^(2+)` Deep blue solution of `Cu(NO_3)_2` Deep blue solution of `Cu(OH)_2 .Cu(NO_3)_2` Solution :`H_(2)S_(g) + Cu_(aq)^(2+) to CUS + 2H_(aq)^(+)` `underset("dilute")(Cus + 10HNO_(3))to underset("Blue")(Cu(NO_(3))_(2) + 8NO_(2) + 4H_(2)O + H_(2)SO_(4) to NH_(3)(aq) [Cu(NH_(3))_(4)]^(2+)` (Deep blue colour)