In qualitative analysis, a black precipitate is obtained when `H_(2)S` is passed through an acidified aqueous solution of a salt . A blue coloured solution is obtained on boiling the preciptate with dilute `HNO_(3)`. The substance obtained on addition of excess of ammonia solution to this blue solution is -

Options

A. deep blue preciptate of `Cu(OH)_(2)`
B. deep blue solution of `[Cu(NH_(3))_(4)]^(2+)`
C. deep blue solution of `Cu(NO_(3))_(2)`
D. deep blue solution of `Cu(OH)_(2).Cu(NO_(3))_(2)`

Answer

B