weschem
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Possible idea to make HCl?
So I wanted to get the expertise of a few of you pros on making HCl. I dont know if this would work but it goes as follows:
Set up a mini electrolysis apparatus for just normal H20 using a dish and 1 test tube and 1 glass tube some 9volts wiring and carbon electrodes. The
electrode that produces the O2 gas will occur in the test tube. The electrode that catalyzes the separation of H+ gas will flow into the glass tube.
The glass tube will run and hook through a stoppered glass bottle that sits in an ice bath. Now another stoppered bottle that is filled with normal
bleach will have a glass tube that runs from it to the bottle in the ice bath. So having the 2 gases of H+ and Cl- in the bottle in the ice bath will
yield HCl.
Is this a feasible process or am I just shooting for the stars? If need be I can upload a sketch if it helps visualization.
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plante1999
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This wont work at all.
You can buy some HCl in the Canada and in the US. You can make it using salt and phosphoric acid, sulphuric acid or sodium bisulphate.
To a lesser extend (which I don't recommend for beginner) is catalyzed union of the elements.
I never asked for this.
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weschem
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Is it that the mixing of H(g) and Cl(g) isnt enough to cause the reaction of HCl or the processes described wont yield H or Cl gas?
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blogfast25
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Quote: Originally posted by weschem  | | Is it that the mixing of H(g) and Cl(g) isnt enough to cause the reaction of HCl or the processes described wont yield H or Cl gas?
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All chemical reactions require a minimum temperature at which they proceed at an appreciable rate (see 'collision theory'). At RT H2 and Cl2 do not
combine spontaneously.
But at highr temperature Cl2 can be 'burned' in a H2 atmosphere (or vice versa) and yield 100 % HCl. Not for the beginner.
[Edited on 10-11-2012 by blogfast25]
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weschem
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This is purely hypotheical. This is for a school research project and wont be doing it myself. So if I heated the mixture the H and Cl ions they would
be in an excited state and would react with each other to form HCl.
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blogfast25
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It’s not really a question of ‘excited state’. Also, there are no ions involved the reaction is between H2 molecules and Cl2 molecules.
At ‘low’ temperature the H2 and Cl2 molecules have ‘low’ kinetic energy and most collisions between the two are elastic (non-reactive) and no
HCl is formed. As temperature goes up, so does the average kinetic energy of the reagent molecules and more of these collisions result in reactive
collisions. Essentially it’s a question of increasing the probability of a given collision to be reactive rather than elastic: that probability goes
up with temperature.
[Edited on 10-11-2012 by blogfast25]
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weschem
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ah well i guess its back to the drawing board. Thanks for the help.
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AJKOER
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Reaction of H2 and Cl2 in UV light, see page 5 at https://docs.google.com/viewer?a=v&q=cache:G8sGJ_FIU-oJ:...
Note the picture of how the Mercury lamp is forming the HCl to react with Iron.
See also http://chemed.chem.purdue.edu/demos/main_pages/10.7.html . Here is an extract:
"Explanation (including important chemical equations):
The UV radiation from the flash initiated the reaction between the H2 and Cl2 gas. The reaction proceeds via a chain-reaction mechanism.
overall reaction: H2 + Cl2 ---> 2 HCl
initiation: Cl2 + hv ---> 2 Cl ·
propagation: Cl · + H2 ---> HCl + H·
H· + Cl2 ---> HCl + Cl ·
termination: 2 H· ---> H2
2 Cl · ---> Cl2
H· + Cl · ---> HCl
The enthalpy for the overall reaction is -184.6 kJ per two moles of HCl. However, the enthalpy for the initial step is 243.36 kJ per mole of Cl2.
This corresponds to the energy carried by photons with a wavelength of 491.5 nm This reaction is catalyzed by light toward the violet end of the
visible spectrum."
Also, unmentioned but an important safety point, to quote (http://www.ucc.ie/academic/chem/dolchem/html/elem001.html ):
"Hydrogen burns in chlorine gas and a mixture of hydrogen and chlorine explodes violently when kindled or exposed to bright sunlight."
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