Question

Following reactions take place during extraction of gold.
$4Au+8C{N}^{-}+2H_{2}O+O_2\to 4\left[Au\right(CN{)}_2{]}^{-}+4O{H}^{-}$
$2\left[Au\right(CN{)}_2{]}^{-}+Zn\to 2Au+\left[Zn\right(CN{)}_4{]}^{2-}$
Zinc in the extraction of gold acts as a/an:

• A. oxidising agent
• B. flux
• C. reducing agent
• D. decomposing agent

Answer 1

The correct option is C reducing agent

$4Au+8C{N}^{-}+2H_{2}O+O_2⟶4\left[Au\right(CN{)}_2{]}^{-}+4O{H}^{-}$

$2\left[Au\right(CN{)}_2{]}^{-}+Zn⟶2Au+\left[Zn\right(CN{)}_4{]}^{2-}$

$0$ $+2$

In the above reaction, Zinc is changing its states from $0$ to $+2$ so zinc is getting oxidized and it acts as reducing agent.