Write the chemical equations involved in the extraction of lead from galena by self-reduction process.

Explanation

To extract lead from galena (PbS) using the self-reduction process, we follow a series of chemical reactions. Here is a step-by-step breakdown of the equations involved in this process:

### Step 1: Roasting of Galena
The first step involves the roasting of galena in the presence of oxygen, which converts lead sulfide (PbS) into lead oxide (PbO) and sulfur dioxide (SO₂).

**Chemical Equation:**
\[ 2 \text{PbS} + 3 \text{O}_2 \rightarrow 2 \text{PbO} + 2 \text{SO}_2 \]

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