An inorganic Compound 'X' on treatment with concentrated `H_2 SO_4` produces brown fumes and gives dark brown ring with `FeSO_4` in presence of concentrated `H_2 SO_4`. Also Compound 'X' gives precipitate 'Y', when its solution in dilute HCl is treated with `H_2 S` gas. The precipitate 'Y' on treatment with concentrated `HNO_3` followed by excess of `NH_4 OH` further gives deep blue coloured solution, Compound 'X' is

Options

A. `Pb(NO_3)_2`
B. `Pb(NO_2)_2`
C. `Cu(NO_3)_2`
D. `Co(NO_3)_2`

Answer

C

Explanation

Nitrates give brown ring test.
`Cu^(2+) + 4NH_3(aq) to underset("Deep Blue")([Cu(NH_3)_4]^(2+)(aq))`
`Cu^(2+) + H_2S overset(H^(+))to underset("Black")(Cu_2S darr)`.