Hydrogen & Chlorine Explosion

Hydrogen and chlorine react explosively if exposed to UV light or a spark. A magnesium flame sometimes initiates this reaction if the gases are contained in a plastic bag. In this clip the magnesium flame did not initiate the reaction so it was started by touching the bag with the burning magnesium. NOTES - The purple line is an aberration of the camera lens caused by the bright light. It isn't actually there. The explosion is louder than indicated in the clip. Look at the effect on the solutions in the fume cupboard to get an idea of the energy.

Category:

Education

Tags:

• hydrogen
• chlorine
• explosion

[antiswattt2]

hey man can you tell me if this gas would go bang if exposed to sun light too? or .. well i have a 200 mW green laser pointer.. maybe if i filled a balloon with hydrogen/chlorine gas... would the laser be able to initiate the gas? that would be quite sick (: i didnt know about this gas mix before i was talking electrolysis with some guy and then disposal of the gas from it..

[ChemPics]

The bond enthalpy of chlorine is 242 kJ Mol-1. This equates to photons in the UV, so I would not expect a laser in the vis range to initiate the reaction. If you contain the gas in a party balloon(approx 2 -3 Ats), the explosion would be more violent than shown.

[antiswattt2]

ya the gas will be confined.. i know about that :P ive been playing so much with small amounts of hydrogen.. i guess you know the acid CuCl? its a lewis acid.. reacts so fast.. and when you light that hydrogen.. its green.. so much fun ^^ but telling my friend to take that balloon and run around on a sunny day would set it off? :P

[ChemPics]

Depends on how much UV penetrates the balloon. Various mechanisms possible, hence different rates.

[The99Gambo]

The reaction can proceed by UV light or by heat. Either way, the radicals are produced which start the chain reaction.

Because this explosion only takes place when the ribbon is close to the bag, I incline to the view that this is therrnally initiated. But there are other clips showing UV initiation on YouTube.