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A colourful oscillating reaction

Description

This experiment provides a visual illustration of a series of interconnected redox equilibria. This repeating cycle of reactions oscillates between red and blue over a period of several minutes.

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
a-colourful-oscillating-r...

 



Apparatus Chemicals

For one demonstration or each pair of students:

Eye protection (Goggles when preparing Solution A - Note 2)

Beakers (100 cm3), 4

Petri dish

Measuring cylinder (10 cm3)

Plastic syringes (1 or 2 cm3), 3

Dropping pipette

Sodium bromate(V) (TOXIC, OXIDISING), 5 g (enough for 10 experiments) or potassium bromate(V) (TOXIC, OXIDISING), 5.5 g

Sodium bromide, 1 g or potassium bromide, 1.2 g

Concentrated sulfuric acid (CORROSIVE), 2 cm3

Propanedioic (malonic) acid (HARMFUL), 1 g

Ferroin indicator solution, 1 cm3

‘Photoflo’ solution, 1 drop (Note 1)

Distilled or deionised water, about 100 cm3

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

 


Read our standard health & safety guidance





Lycèe Faidherbe de Lille


Page last updated October 2015

This experiment provides a visual illustration of a series of interconnected redox equilibria. This repeating cycle of reactions oscillates between red and blue over a period of several minutes.

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.