The equations of chemical reactions occurring during the process areIn the presence of oxygen2PbS+3O2​⟶2PbO+2SO2​By self-reduction2PbO+PbS⟶3 Pb+SO2​Thus 3 moles of O2​ produces 3 moles of Pb i.e. 32×3=96 g of O2​ produces 3×207=621 g of Pb So 1000 g(1 kg) of oxygen will produce96621​×1000​=6468.75 g=64687 kg≈6.47 kg​