During the extraction of gold the following reactions take place.` Au + CN^(-) + H_(2)O overset (O_(2)) to [X]`
`[X] + Zn rightarrow [Y] + Au`
X and Y are respectively.

Options

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

Answer

D

Explanation

During the extraction of gold.
`Au + CN^(-) + H_(2)O (overset(O_(2))) to [Au(CN)_(2)]^(-)`
`[Au (CN)_(2)]^(-) + Zn rightarrow [Zn(CN)_(4)]^(2-) + Au`
Here `[X] = [Au(CN)_(2)]^(-)` and `[Y] = [Zn(CN)_(4)]^(2-)`