Q.
What is the concentration of O2 in a freshwater stream in equilibrium with air at 30∘C and 2.0 bar? Given, KH
(Henry’s law constant) of O2=2.0×10−3mol/kg bar at 30∘C
In this case, KH has been given in the unit of mole/kg bar
Thus, solubility of O2 (or concentration) =KHPgas χo2 (in air) = 0.21 ∴po2=pairχo2=0.21bar ∴ Solubility =kgbar2.0×10−3mol×0.21bar =4.2×10−4×32g/kg =1.344×10−3g/kg