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Blue flask

Tools: 250 ml flask, stopper

Chemicals: sodium hydroxide, glucose (you can buy at the drugstore as grape sugar), methylene blue

Procedure: In 100 ml of water was dissolved 2 g of sodium hydroxide and 2 g of glucose. to a solution of add 4 ml of 0.1% solution of methylene blue. The flask with a rubber stopper. Blue solution for a few minutes completely decolorized. When shaking reappear blue color of the solution.

The phenomenon is caused by oxidation and reoxidation of methylene blue (her ox-form is colorless, redox-form blue).

If there is no convincing attempt, just for a moment uncork the flask (flask with gets oxygen), stopper and again is repeated.

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