How to Make Chlorine Gas


Chlorine gas is a pale greenish yellow color. (W. Oelen)

Chlorine gas is a pale greenish yellow color. (W. Oelen)

These are instructions for preparing chlorine gas (Cl2) from potassium permanganate and concentrated hydrochloric acid.

Reactants

Only two chemicals are needed:

  • potassium permanganate
  • concentrated hydrochloric acid

Gas Preparation

Add concentrated hydrochloric acid dropwise onto a small quantity of potassium permanganate crystals (in a flask). Collect the chlorine gas by upward displacement of air in a hood. Use proper safety precautions. Concentrated hydrochloric acid is extremely caustic. Chlorine gas is toxic.

Reaction

The reaction between hydrochloric acid and potassium permanganate products chlorine gas, manganese dioxide, water, and potassium ions.

6HCl + 2KMnO4 + 2H+ → 3Cl2 + 2MnO2 + 4H2O + 2K+

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