A black coloured compound (A) on reaction with dilute H_(2)SO_(4) gives a gas (B) which on passing in a solution of an acid ( C) gives a white turbidity (D).Gas (B) when passed in an acidified solution of a compound (E) gives a precipitate (F) soluble in dilute HNO_(3).After boiling this solution when an excess of NH_(4)OH is added a intense blue coloured compound (G) is formed. To this solution on addition of acetic acid and aqueous K_(4)[Fe(CN)_(6)] a chocolate brown precipitate (H) is obtained.On addition of an aqueous solution of BaCl_(2) to an aqueous solution of (E) a white precipitate insoluble in dilute HCl is obtained. Identify the compounds from (A) to (H).

A black coloured compound (A) on reaction with dilute H_(2)SO_(4) give

1.	A black coloured compound (A) on reaction with dilute H_(2)SO_(4) gives a gas (B) which on passing in a solution of an acid ( C) gives a white turbidity (D).Gas (B) when passed in an acidified solution of a compound (E) gives a precipitate (F) soluble in dilute HNO_(3).After boiling this solution when an excess of NH_(4)OH is added a intense blue coloured compound (G) is formed. To this solution on addition of acetic acid and aqueous K_(4)[Fe(CN)_(6)] a chocolate brown precipitate (H) is obtained.On addition of an aqueous solution of BaCl_(2) to an aqueous solution of (E) a white precipitate insoluble in dilute HCl is obtained. Identify the compounds from (A) to (H).
Answer» Solution :`CUS+H_(2)SO_(4) to CuSO_(4)+H_(2)S` `2HNO_(3) to 2NO_(2)+H_(2)O+[O]` `H_(2)S+[O]to H_(2)O+S darr ("white")(HNO_(3)` is strong oxidising agent). `CuSO_(4)+H_(2)S to CuS darr +H_(2)SO_(4)` `3CuS + 8HNO_(3) to 3Cu^(2+) + 6NO_(3)^(-)+3S darr +2NO uarr+4H_(2)O.` `2NO_(3)^(2-)+CU^(2+) +4NH_(4)OH to [Cu(NH_(3))_(4)]^(2+) (NO_(3))_(2)` (intense blue coloured solution )+`4H_(2)O` `[Cu(NH_(3))_(4)(NO_(3))_(2)+K_(4)[Fe(CN)_(6)] to Cu_(2)[Fe(CN)_(6)] darr` (chocolate BROWN). `Ba^(2+)+CuSO_(4) to BaSO_(4) darr ("white") +Cu^(2+)`