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

Explanation

To extract lead from galena (lead sulfide, PbS) using the self-reduction process, we follow a series of chemical reactions. Here’s a step-by-step breakdown of the process along with the relevant chemical equations:

### Step 1: Roasting of Galena
The first step involves roasting the galena in the presence of excess oxygen. This process converts the 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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