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Blue Chromium Clouds

Blue Chromium Clouds is a chemistry experiment in which Potassium Dichromate reacts with the sulphuric acid in the presence of hydrogen peroxide to produce chromium(III) sulfate, oxygen, potassium sulfate and water.

In this Blue Chromium Clouds activity we add the orange coloured crystals of potassium dichromate to the solution of sulphuric acid and the hydrogen peroxide. The reaction takes place and the orange coloured crystals immediately change into blue coloured clouds in the solution.

main image,Blue Chromium Clouds

Safety First! Adult supervision required. Wear protective eye wear and clothing. Don’t eat/drink your experiments.

Materials and tools required

materials,Blue Chromium Clouds

Chemicals:

  • Hydrogen Peroxide
  • Sulphuric Acid
  • Potassium Dichromate
  • Distilled Water

Apparatus

  • 1000 ml conical flask
  • Pippette
  • Stirrer
  • Spoon

Video on the YouTube for experiment

What to do!

Step 1 – Add 1000 ml of distilled water in a conical flask.

Step 2 -Add few drops of hydrogen peroxide.

Step 3 – Add few drops of Sulphuric Acid.

Step 4 – Stir the solution.

Step 5 – After mixing, add potassium dichromate crystals.

Step 6 – The orange potassium dichromate crystals change into blue colour!                   Observe the blue clouds.

Images for instructions

Working principle of the activity

What is happening in this Blue Chromium Clouds experiment is, the reaction between Potassium Dichromate, Hydrogen Peroxide and Sulphuric Acid. This reaction takes place as:

K2Cr2O7 + 4H2SO4 + 3H2O2 → Cr2(SO4)3 + 3O2 + K2SO4 + 7H2O

Here, Potassium dichromate is reacting with sulfuric acid and hydrogen peroxide to produce chromium(III) sulfate, oxygen, potassium sulfate and water. Initially chromium(IV) peroxide is formed as a product which is blue in colour and appear as Blue Chromium Clouds.