A green ore (A) of a metal present as a double /mixed compound is treated with HCl and then H_(2)S is passed in the solution. A back precipitate (B) is obtained, that is insoluble in yellow ammonium sulphide. The precipitate is dissolved in HNO_(3) and then excess of NH_(4)OH is added. The solution becomes coloured but this colour is discharged upon addition of KCN in excess due to the formation of compound (C). The solution of (A) in H_(2)O liberates a colourless and odourless gas on reaction with dilute H_(2)SO_(4) and solution of (A) gives white precipitate on addition of BaCl_(2) solution. After dissolving the precipitate in HNO_(3) aqueous K_(4)[Fe(CN)_(6)] is added and a precipitate is formed.

A green ore (A) of a metal present as a double /mixed compound is trea

1.	A green ore (A) of a metal present as a double /mixed compound is treated with HCl and then H_(2)S is passed in the solution. A back precipitate (B) is obtained, that is insoluble in yellow ammonium sulphide. The precipitate is dissolved in HNO_(3) and then excess of NH_(4)OH is added. The solution becomes coloured but this colour is discharged upon addition of KCN in excess due to the formation of compound (C). The solution of (A) in H_(2)O liberates a colourless and odourless gas on reaction with dilute H_(2)SO_(4) and solution of (A) gives white precipitate on addition of BaCl_(2) solution. After dissolving the precipitate in HNO_(3) aqueous K_(4)[Fe(CN)_(6)] is added and a precipitate is formed.
Answer» It is a reddish brown precipitate of `Cu_(2)[Fe(CN)_(6)]`. It is a reddish brown precipitate of `K_(2)Cu_(3)[Fe(CN)_(6)]_(2)` It is a chocolate brown precipitate of `Cu_(2)[Fe(CN)_(6)]`. It is a chocolate brown precipitate of `K_(2)Cu_(3)[Fe(CN)_(6)]_(2)` ANSWER :C