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Describe the role of NaCN in the extraction of gold from gold ore. Write chemical equations for the involved reactions. |
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Answer» SOLUTION :Gold is leached with a solution of NaCN in the presence of AIR (for `O_2`) from which the metal is OBTAINED later by displacement. `4Au (s) +8CN^(-) (aq) +2H_(2)O +O_(2)(g) to 4[AU(CN)_(2)]^(-) (aq) +4OH^(-) (aq)` `2[Au(CN)_(2)]^(-) (aq) +Zn (s) to [Zn (CN)_(4)]^(2-) (aq) +2Au (s)`. |
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