The Blue Bottle Experiment (Reaction Only)

This reaction sees an alkaline solution of glucose acting as a reducing agent (a species that is oxidised), to reduce the methylene blue to a colourless form. When the solution is disturbed, i.e. shaking the reaction vessel, the oxygen in the air around the solution is reintroduced and causes the oxidation of the methylene blue back to its blue form. As the oxygen, which has been dissolved in the solution, is consumed the methylene blue is slowly reduced back to its colourless form by the remaining glucose. This reaction can be cycled many times by further shaking of the reaction vessel. This reaction forms the enolate of glucose which then goes on to participate in a redox reaction between the methylene blue and the glucose enolate. The glucose is oxidised to gluconic acid, which takes the form of sodium gluconate in the alkaline solution. The colourless form of methylene blue is called leucomethylene blue.

[ScienceMarshall]

Ooh, love this reaction. I could sit there and do it for hours.