Question

In cyanide extraction process of silver from argentite ore, the oxidizing and reducing agents are respectively.

• A. $HN{O}_3$ and $CO$
• B. $HN{O}_3$ and $Zn$ dust
• C. $O_2$ and $Zn$ dust
• D. $O_2$ and $C{O}_2$

Answer 1

The correct option is C $O_2$ and $Zn$ dust

In cyanide extraction process of silver from argentite ore, the oxidising agent is $O_2$ and the reducing agent is $Zn$ dust.
$4\text{Roasted gold ore}+8C{N}^{-}+O_2\left(g\right)+2H_{2}O\left(aq\right)\to \left[Au\right(CN{)}_2{]}^{-}\left(aq\right)+4O{H}^{-}\left(aq\right)$
$2\left[Au\right(CN{)}_2{]}^{-}\left(aq\right)+Zn\left(s\right)\to \left[Zn\right(CN{)}_4{]}^{2-}\left(aq\right)+2Au\left(s\right)$

Hence, option (b) is correct.