Air is injected through fine$-$bubble diffusers into a

basin $3\mathrm{.}5$ m deep in a well$-$mixed, batch $($no flow$)$

reactor at $25$C$.$ With sufficient time, the water will

reach equilibrium with the air and no mass transfer

is occurring. Under these conditions, answer the

following:

$($a$)$ What is the pressure on the bubbles $($in atm$)$ at

the bottom, middle, and top of the tank?

$($b$)$ What is the concentration of oxygen $($in milligram per liter$)$ in the bubbles at each of the three

points of interest in part $($a$).$

$($c$)$ What is the final $($equilibrium$)$ concentration of

oxygen in the water $($c

L $),$ in milligram per liter?

Because the basin is completely mixed, assume

that the water is$,$ on average, at equilibrium with

bubbles at the mid$-$depth pressure.

$($d$)$ What would the value of c

L be if the injected gas

were pure oxygen instead of air?