Practice problem $3\mathrm{.}1$:

Lead $(Pb)$ is produced by flash smelting of galena $(PbS)$ concentrate. There is generation

of slag containing PbO according to the following reaction:

$Pb(l)+0\mathrm{.}5O_2(g)=$PbO$(S)Gat1000C=-95\mathrm{.}3k\frac{J}{m}$olPbO

If you want to generate a slag with activity of PbO no higher than ${10}^{-4},$ what's the highest

oxygen pressure you can have while producing $Pb$ with an activity of $0\mathrm{.}95.$