sequence

helooooooooooooooooooooooooooo

plz try this one.....i have not been able to find some

A - S^2- salt , B - SO₂ , C - aqueous Ba⁺² salt , D - BaSO₃ , E - CuCO₃ , white ppt. - BaSO₃ , F - CuSO₃ , soluble - Cu(NO₃)₂ , G - Cu(OH)₂ , H - Cu₂[Fe(CN)₆] ,

First hint frm the chocolate ppt. it needs to be Cu₂[Fe(CN)₆]. thus,now proceeding in the backward direction , till E , all are Cu²⁺ compounds.

now,its a jaggle deciding E. its sure B is SO₂ and to get white ppt. frm E, E needs to hv sulphate,sulphite or carbonate. But sulphate and sulphite won't react wid SO₂. Thus,its the carbonate.

but, no information about A , except that it would be a sulphide ion.