1.
Main source of lead is galena. It is converted to Pb by:

(X) PbS+O2PbO+SO2\text{PbS} + \text{O}_2 \rightarrow \text{PbO} + \text{SO}_2; PbO+CPb+CO2\text{PbO} + \text{C} \rightarrow \text{Pb} + \text{CO}_2

(Y) PbS+O2PbO+PbS\text{PbS} + \text{O}_2 \rightarrow \text{PbO} + \text{PbS}; heating Pb+SO2\rightarrow \text{Pb} + \text{SO}_2

(Z) PbS+O2PbO+SO2\text{PbS} + \text{O}_2 \rightarrow \text{PbO} + \text{SO}_2; PbO+COPb+CO2\text{PbO} + \text{CO} \rightarrow \text{Pb} + \text{CO}_2

Self-reduction process is: