Hydrogen reacts with chlorine

Hydrogen flame or explosion in chlorine forms white smoke

Scientific name: Hydrogen oxidation with chlorine is a photosensitive, free radical reaction


Hydrogen and Chlorine Reaction

Fire and Flame 44 - Hydrogen and Chlorine Bang

by Royal Society Of Chemistry

Hydrogen & Chlorine Explosion

by ChemPics

Fire and Flame 43 - Hydrogen Flame in Chlorine

The sound of hydrogen burning in a large container of chlorine

by endimion17

Photochemical reaction between chlorine and hydrogen

by andycapo123

Hydrogen and chlorine reaction(add light, boom!)

by chemistry858


Wear eye protection goggles. Work with poisonous gases only outdoors or in a hood.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

H2 + Cl2 → 2 HCl


  1. Chlorine
  2. Hydrogen

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 and hydrogen gases. There are many different ways.
  2. Collect chlorine and hydrogen gases into a chemical cylinder or test tube. Close it.
  3. Initiate the reaction using a powerful light source or by spark.
  4. Observe the explosion.

Scientific background

Chlorine gas is a strong oxidant. Hydrogen is oxidized to HCl, which forms the smoke. The reaction is a free radical reaction. It requires temperature or light initiation. It's best to use an ultraviolet light source, because it has the highest energy of radiation.


Published on 26 March 2015

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