In the cyanide extraction process of silver from argentite ore, what are the oxidizing and reducing agents used?

Options

A. `O_(2)` and CO respectively.
B. `O_(2)` and Zn dust res pectively
C. HNO, and Zn dust respectively
D. `HNO_(3)` and CO respectively

Answer

B

Explanation

In the extraction of silver, `Ag_(2)` S is leached with KCN in presence of air:
`Ag_(2) S + Na CN +O_(2)`
`rarr Na [ Ag (CN_(2))_(2)] + Na_(2) S_(2) O_(2)`
Thus `O_(2)` is an oxidant
`2Ag (CN)_(2)^(-) +Zn rarr [ Zn (CN)_(4)]^(2-)+ 2Ag darr`