Zinc is extracted from zinc blende. The zinc blende is roasted. The solid product is mixed with coke in a blast furnace from which zinc vapours emerge.
What is the reducing agent in the extraction?

Explanation

To determine the reducing agent in the extraction of zinc from zinc blende, we can follow these steps:

### Step 1: Understand the Process of Extraction
Zinc is extracted from zinc blende, which is primarily composed of zinc sulfide (ZnS). The first step in the extraction process is roasting, where the zinc sulfide is converted into zinc oxide (ZnO) in the presence of air.

### Step 2: Identify the Reaction During Roasting
The roasting process can be represented by the following chemical equation:
\[ 2 \text{ZnS} + 3 \text{O}_2 \rightarrow 2 \text{ZnO} + 2 \text{SO}_2 \]
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