Write and explain the reactions involved in the extraction of gold.

Explanation

To extract gold, the process primarily involves the leaching of gold ore using cyanide. Here is a step-by-step explanation of the reactions involved in the extraction of gold:

### Step 1: Leaching of Gold Ore
The first step in the extraction of gold is the leaching process, where gold is dissolved in a cyanide solution. The reaction can be represented as follows:

\[ 4 \text{Au (s)} + 8 \text{CN}^- (aq) + 2 \text{H}_2\text{O} (l) + \text{O}_2 (g) \rightarrow 4 \text{[Au(CN)}_2]^− (aq) + 4 \text{OH}^- (aq) \]
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