I'm trying to finish a lab report on the Blue Bottle Demostration where glucose is added to a solution of NaOH. Then Indigo carmine is added so the solution would go from red to yellow to green (My teacher called it the stop light reaction :D) I need to figure out why does the process eventually stop. Here is what I think: Since O2 in the flask is what re-oxidizes the indigo carmine to reform the initial colour at equilibrium, with out O2, the reaction will eventually stop. My question is, what happened to the O2 that oxidizes the indigo carmine? does it just stay there?