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The ‘blue bottle’ experiment

Description

A colourless solution in a flask is shaken. It turns blue and then gradually back to colourless. The cycle can be repeated many times.

Type of Activity

:
demonstration

Audience

:
Teacher

Age Group

:
11 to 18 years

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
the-blue-bottle-experimen...

 



Apparatus Chemicals

Eye protection: goggles should be worn when preparing the solution

For each demonstration:

Conical flask (1 dm3)

Stopper or bung, to fit flask

Potassium hydroxide (CORROSIVE, IRRITANT), 8 g

Glucose (dextrose), 10 g

Methylene blue (HARMFUL), 0.05 g

Ethanol (IDA – Industrial Denatured Alcohol) (HIGHLY FLAMMABLE, HARMFUL), 50 cm3

Access to a nitrogen cylinder (optional)

Refer to Health & Safety and Technical notes section below for additional information.

 



 






Page last updated October 2015

A colourless solution in a flask is shaken. It turns blue and then gradually back to colourless. The cycle can be repeated many times demonstrating the redox equilibrium

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany Practical Physics and Practical Biology.

The experiment is also part of the Royal Society of Chemistry's Continuing Professional Development course: Chemistry for non-specialists