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Catalysis of the reaction between sodium thiosulfate and hydrogen peroxide

Description

Hydrogen peroxide oxidises sodium thiosulfate to sulfuric acid. The pH change can be followed using universal indicator. Adding an ammonium molybdate catalyst speeds up the colour change.

Credits

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



Apparatus Chemicals

Eye protection

The teacher will require:

Flasks (1 dm3), 4

Measuring cylinder (100 cm3)

Beaker (100 cm3)

Sodium thiosulfate-5-water, 8.7 g.

Sodium ethanoate-3-water (sodium acetate tri-hydrate), 3.8 g or anhydrous sodium ethanoate, 2.3 g

Sodium hydroxide (CORROSIVE), 0.5 g

Ammonium molybate(VI) (HARMFUL), 0.08 g

Hydrogen peroxide, 100 'volume' (HARMFUL), 14 cm3

Universal indicator solution (HIGHLY FLAMMABLE), a few cm3

Deionised or distilled water, 1.1 dm3

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

 

 






Hydrogen peroxide oxidises sodium thiosulfate to sulfuric acid. The pH change can be followed using universal indicator. Adding an ammonium molybdate catalyst speeds up the colour change.

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.