Close
Planned Maintenance
We’ll be carrying out essential maintenance work beginning on Saturday 15th June 2019 at 8:30 am through to Sunday 16th June 2019 at 11:30 pm (BST).

During this time our website may be temporarily affected. We apologise for any inconvenience this might cause and thank you for your patience.
Close
Learn Chemistry is changing
Our new website is coming soon. Find out more

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