Combustion of potassium in chlorine

The cylinder is filled with white smoke after adding potassium

Scientific name: Potassium oxidation with chlorine


Potassium and chlorine

by ChemPics

Reacting alkali metals with chlorine

Heated Potassium Placed in Chlorine

Взаимодействие хлора с калием


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Reaction formula

2 K + Cl2 → 2 KCl


  1. Chlorine
  2. Potassium

Step-by-step instruction

WARNING! This experiment is dangerous! You should NOT perform this at home. ONLY carry out this experiment, if you are a trained chemist, and you understand local safety and legal requirements, which are required to perform such experiments

  1. Obtain chlorine gas. There are many different ways.
  2. Collect chlorine gas into a chemical cylinder or test tube.
  3. Quickly add potassium into the cylinder with chlorine.
  4. Heat the pieces of potassium through the glass over a gas burner or alcohol lamp.
  5. Watch the cylinder fill with white smoke.

Scientific background

Chlorine gas is a strong oxidant. Metallic potassium is oxidized to potassium chloride, which forms the smoke. The interfacial reaction takes place very slowly, so heating is necessary.


Published on 26 March 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst