A test tube, $1\mathrm{.}5$ cm a diameter and $12$ cm tall, is partly filled with a solution of alkaline pyrogallate. The depth of the empty space above the solution is $5$ cm$.$ The total pressure is $1$ atm $(1\mathrm{.}013$ x $10\backslash$deg Pa$)$ and the temperature is $25\backslash$deg C$.$ Air is assumed to contain $21\%$ oxygen $($A$)$ and $79\%$ nitrogen $($B$).$ Dug is taken as $0\mathrm{.}21$ cm$"/.$ Alkaline pyrogallate readily dittuses oxygen but nitrogen is virtually insoluble in it$,$ Calculate the flux of oxygen $($in mol$/$s$)$ from air in alkaline pyrogallate at steady state