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How To Demonstrate the Catalytic Oxidation of Ammonia using Chromium (III) Oxide

How To Demonstrate the Catalytic Oxidation of Ammonia using Chromium (III) Oxide

In this video, we showcase the catalytic oxidation of ammonia utilising Chromium (III) Oxide as the catalyst.

Paul Cook guides you through each step of the experiment, providing insights into the chemical reactions and the underlying principles of catalysis.

Be amazed as we carefully add concentrated Ammonia Solution to a large round bottom flask, creating a vapour that is then mixed with air.

Watch closely as the heated Chromium (III) Oxide, glowing red hot, is introduced into the flask, triggering a stunning display of sparks.

With safety as our priority, we conducted this experiment in a fume cupboard, ensuring the proper handling of chemicals and adherence to safety protocols.

This experiment provides students with a tangible application of theoretical concepts, fostering a deeper understanding of catalysis, redox reactions, and the practical applications of inorganic chemistry.


You will need:

  • Safety screen
  • Heatproof mats
  • Bunsen burner
  • Matches, splint, or lighter
  • Deflagration spoon
  • Large round bottom flask (5L) with bung – (A large conical flask or cylinder can be used as an alternative)
  • 10ml x Concentrated 35% 880 Ammonia Solution
  • Chromium (III) Oxide



  1. Set up the experiment in a fume cupboard ensuring all necessary safety precautions are in place.
  2. Place the safety screen and heatproof mats on the working surface.
  3. Light the Bunsen burner and adjust it to the safety flame.
  4. Carefully add 10ml of concentrated Ammonia Solution to the large round bottom flask.
  5. Insert the bung firmly into the flask and hold both the bung and the base of the flask securely.
  6. Gently swirl the solution in the flask to ensure the Ammonia vapours mix thoroughly with the air.
  7. Move the bunged flask to a safe location on the side of the working area.
  8. Fill the deflagration spoon with an appropriate amount of Chromium (III) Oxide.
  9. Heat the deflagration spoon using the Bunsen burner until the Chromium (III) Oxide becomes red hot and begins to glow.
  10. Prepare to switch off the lights, ensuring that this step is coordinated with the experiment.
  11. Lift the bung from the flask and carefully tip the heated Chromium (III) Oxide into the flask, observing the spark reaction.
  12. Promptly replace the bung on the flask after the reaction.
  13. If there is sufficient ammonia gas left, repeat the final stage of the experiment to further demonstrate the catalytic oxidation of ammonia.


Safety Precautions:

  • Perform the experiment in a fume cupboard to prevent the release of any potentially harmful gases.
  • Wear appropriate personal protective equipment, including gloves and safety goggles.
  • Handle the chemicals and apparatus with care to prevent any spills or accidents.
  • Ensure that all participants are aware of the safety protocols and emergency procedures in case of mishaps.

All health and safety measures are the responsibility of the teacher doing the demonstration. A thorough risk assessment should be carried out and guidance procedures followed. It is suggested that you practice before demonstration in front of a class and this experiment should be conducted under the supervision of a knowledgeable instructor or with the assistance of an experienced professional.

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