In the process of extraction of gold.
Roasted gold ore `+CN^(-)+H_(2)O overset(O_(2))rarr [X]+OH^(-)`
`[X]+Znrarr [Y]+Au`
Identify the complexes `[X] ` and `[Y]`.

Options

A. `Au(CN)_(2)]^(-), [Zn(CN)_(4)]^(2-)`
B. `[Au(CN)_(4)]^(3-), [Zn(CN)_(4)]^(2-)`
C. `[Au(CN)_(2)]^(2-), [Zn(CN)_(6)]^(4-)`
D. `[Au(CN)_(4)]^(-), [Zn(CN)_(4)]^(2-)`

Answer

A

Explanation

`overset(-)(CN)(aq) + H_(2)O overset(o_(2))rarr[X] +[OH^(-)]`
`[X]+Znrarr[Y]+Au`
Identify the complexes [X]and[Y].