Photochemical Reaction of Hydrogen and Chlorine
ฝัง
- เผยแพร่เมื่อ 27 ก.ย. 2024
- Different colors of LED light illuminate a small corked test tube of hydrogen and chlorine gas with no reaction; ultraviolet light causes an explosion that shoots the cork across the room. The gas mixture is made by the electrolysis of hydrochloric acid 8M. A water bath allows for filling the tubes under water. The tubes are quartz.
References
* Richard Schwenz and Lynn Geiger. "Photon-Initiated Hydrogen-Chlorine Reaction." Journal of Chemical Education 76.4 (1999): 470.
* Shakhashiri, Bassam Z. "Chemical Demonstrations: A Handbook for Teachers of Chemistry." Madison: The University of Wisconsin Press, 1983. ( books.google.co...)
That was an excellent demonstration! 👍👏
Even though I expected something, it still made me jump
QUESTION............Why didn't BLUE work? Or was it working but just to slow? Because i have made chlorine free radicals using LED blue light. Of course i had 18 LEDs and not just one. I mean you only need 494nm light to homolytically cleave a Cl/Cl bond which is almost in the green wavelength. And LED blue light is like 450 to 460nm light which is stronger than 494nm light
What did you make them for?
Many thanks for the upload.
Very interesting!
Thank you!
Have you heard about the MHD engine operating on alternating magnetic and electric fields
Can we boil the water first to drive off a lot of the dissolved oxygen and then bubble the chlorine through it as it cools down? It would be nice to be able to cut down on the amount of chlorine we have to generate, as well as shorten the time until chlorine saturation.
Yes, that would work, the solubility of oxygen in water decreases as the temperature increases. It's precisely for that reason why fish in stagnant ponds don't do well during heat waves.
Pretty awesome video :D
Glad you liked it!
It wouldn't matter what the amplitude/brightness of the light is in order to catalyze the reaction due to the energy of the light only depending on frequency. The brightness would just increase the likelihood that an electron would be energized enough to allow bonding of H and Cl due to there being more photons being "thrown around". At this scale, it would be a negligible change in probability anyway. Can anybody back me up or correct me?
Well, I'm not a chemist but I like chemistry and I'm looking into chlorine photolysis reactions now, and I believe you are mostly wrong. Hydrogen burns in chlorine, and in the equimolar concentrations in that tube, that reaction is explosive. It's an exothermic reaction that sustains itself once the mix has ignited.
What the UV does is it cleaves the bond between the atoms in the Cl2 molecule, creating two Cl radicals. These reactive radicals react with the H2, creating HCl, and a H radical. The H radical goes on to react with another Cl radical or a Cl2 molecule and make more HCl, maybe more radicals. The heat in the flame creates more radicals from other molecules, and the reaction is sustained. Well, to ignite that flame to begin with, you need to hit enough Cl2 molecules with UV to create enough Cl radicals in a short enough time, that their combined reaction with surrounding H2 generates enough heat to sustain the reaction. Otherwise you'd just slowly convert the gas mix into HCl in the path of the light from the UV diode, in case it was too weak.
Two other cool videos on this I just watched were called Fire and Flame 43, and Fire and Flame 44 from Royal Society Of Chemistry... observe how it takes a while to ignite the mix in the second video where he uses burning Mg, and he has to hold it real close. Burning Mg outputs a lot of UV.
One thing I don't understand is what the guy said about how O2 works as a catalytic poison for the reaction. Usually its the other way around, Cl or Br is used to poison the flame when O2 is the oxidant, in flame retardants. Maybe it works the other way around too.
That's all I've got!
You are mostly correct. Intensity of light, ie the amplitude of light, isn't a factor here. The specific frequency (ie color) is what determines if the energy of the wave is absorbed or passes by. If the frequency is correct, the wave will be absorbed and increase the energy level of the electrons allowing for a restructuring. Any other frequencies, regardless of the amount, will not generate that excited state.
Pretty much, with an edge case where two photon absorption can occur with enough power density, where for example two red photons could be absorbed simultaneously to effectively induce effects that would otherwise only possibly caused by a single blue photon. This effect is used in two photon microscopy and two photon lithography
Are you okay near HCl gas without gas mask?
Remember to open the windows.
congratulations!!
amazing thank you so much
This was awesome
Thank you so much sir....✨✨✨
Interesting that energy of light is really frequency dependant and not amplitude
At the very end you mentioned the humidity in the air. Doesn't the HCl become hydrochloric acid when it meets that humidity?
Also, was there any Oxygen present in the test tube with the hydrogen and chlorine?
@@InterBalance No, that was addressed earlier in the video.
@@OxBlitzkriegxO, I do see that the topic of oxygen in the tube was addressed. But I'm still curious about the HCl becoming hydrochloric acid when it meets the water in the air!
@@InterBalance You're correct. HCl or hydrogen chloride is a gas, but it can dissolve in water at concentrations of up to 38-40% in which case it's called hydrochloric acid. And the same goes for hydrogen bromide and hydrogen iodide, which can dissolve in water at up to 69% and 57% m/v concentration.
Pls how can I get UV light for my project
that nice
Did they try with Infrared lights?
Infrared would not have the energy to trigger it.
🙏🙏🙏❤️🙏🙏🙏
The scientist ignored the presence of water vapor in the test tube, which is stupid.
What is different? Perhaps some HCl dissolved in that water
I guess it's a zero order reaction
dunno why i watched this
Thats cool
0:06 Hydrogen and Chlorine in da hood .😂
green photons .... hahaha omg ... correct this please
They _looked green_ when we ordered them from the catalog! 🟢 🟢 🟢 - j q t -
Go on you are fantastic i love science
Look my version this experiment in my last video.
Sir why it's colour is green when it's reacts with hydrogen means when chlorine reacts with hydrogen so why it's colour is green
Where the colour of hydrogen is white and chlorine is green
The gas reacts under ultraviolet light, not green.
why don't you use salt instead of hydrochloric acid? you don't produce oxygen with salt at all.
Nerdbomber alert
What wave length of uv did you use sir?