When of the following precipitate is soluble in excess of `NH_(3)` solution?

Options

A. `Zn^(2+),Cd^(2+)`
B. `Hg^(2+),Ag^(+)`
C. `Cu^(2+),Pb^(2+)`
D. `Mn^(2+),Ni^(2+)`

Answer

A

Explanation

Both `Zn^(3+) and Cd^(3+)` cations can be separated by passing `H_(2)S` gas in acidic as well as well as in neutral medium.
(i) `Zn^(3+)+H_(2)S to ` No ppt.
(ii) `Cd^(3+)+H_(2)S tounderset("yellow ppt")(CdS darr)`