Write the chemical reaction involved in the extraction of gold by cyanide process. Also give the role of zinc in the extraction.

Explanation

### Step-by-Step Solution:

1. **Understanding the Cyanide Process**: The cyanide process, also known as the cyanidation process, is a method used to extract gold from its ore. In this process, gold is treated with a cyanide solution.

2. **Chemical Reaction for Gold Extraction**:
The first step involves the reaction of gold with cyanide ions, water, and oxygen to form a gold cyanide complex. The chemical reaction can be represented as:
\[
4 \text{Au} + 8 \text{CN}^- + 2 \text{H}_2\text{O} + \text{O}_2 \rightarrow 4 \text{[Au(CN)_2]}^- + 4 \text{OH}^-
...