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  3. Chemistry
  4. Following reactions take place during extraction of gold. 4Au + 8CN- + 2H2O + O2 → 4[Au(CN)2]- + 4OH- 2[Au (CN)2]- + Zn → 2Au + [Zn(CN)4]2- Zinc in the extraction of gold acts as a/an

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Q. Following reactions take place during extraction of gold.
$4Au + 8CN^- + 2H_2O + O_2 \to 4[Au(CN)_2]^- + 4OH^-$
$2[Au (CN)_2]^- + Zn \to 2Au + [Zn(CN)_4]^{2-}$
Zinc in the extraction of gold acts as a/an

General Principles and Processes of Isolation of Elements

Solution:

$4 Au +8 CN ^{-}+2 H _{2} O + O _{2} \longrightarrow 4\left[ Au ( CN)_{2}\right]^{-}+4 OH ^{-}$
$2\left[ Au ( CN )_{2}\right]^{-}+ \underset{0}{Zn} \longrightarrow 2 Au +\underset{+2}{\left[ Zn ( CN )_{4}\right]^{2-}}$
In the above reaction, Zinc is changing its states from 0 to $+2$ so zinc is getting oxidized and it acts as reducing agent.