# Question: four liters l of ethanolbased ch3ch2oh gasoline are accidently released...

###### Question details

Four liters (L) of ethanol-based (CH3CH2OH) gasoline are accidently released into an aquifer and the indigenous microbes completely oxidized this amount using the oxygen dissolved in the water as the oxidizing agent. i) Write the redox half reactions and derive the balanced stoichiometric equation for the process, and ii) calculate the amount of oxygen required (in grams) for compete oxidation of the ethanol. iii) How many liters of aquifer water contain this amount of oxygen? Herny's Law constant for oxygen under in situ conditions (20 °C and 0.5 atm pressure) is KH-4x10^4 atm and the air in contact with the aquifer contains 20% O2. The density of ethanol in gasoline is ρ= 575g/L, Atomic weights: C-12, O-16, H-1. (30 points)

Answer: 1,081,081 L will be required (lots of water!)

Could someone do a step-by-step explanation of part iii? I have been able to solve the first two steps. However the third, my math seems off when using Henry's law. I rearranged the formula to solve for the liters. However am I confused on whether to use the mols of water or the mols of O2, even though I know Henry's law applies to gas. But how would I get to the liters of water from there?