In qualitative analysis when H2S is passed through an aqueous solution of salt acidified with dil. HCl, a black precipitate is obtained. On boiling the precipitate with dil. HNO3, it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives _________.
when H2S is passed through an aqueous solution of salt acidified with dilute HCl
Cu2+ + H2S 
CuS + 2H+
Black precipitate of copper sulphide is formed. When copper sulphide is heated with dil. HNO3 it gives blue colour of copper nitrate( on boiling), when aqueous solution of ammonia is added to it deep blue colour of tetraammine copper(II)sulphate [Cu(NH3)4]2 is obtained.
CuS + dil.HNO3
Cu(NO3)2
Cu(NO3)2 + 4NH3
[Cu(NH3)4]2+
Hence the correct option is (ii)
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