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Romix
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HOCl → HCl
Hello Dear forum members. Have interesting question for you.
How to decompose HOCl into HCl? Both are products of bubbling Cl2 into water. I need HCl, not much of it and taking my whole distillation setup 3k
miles away is just stupid to make couple hundred ml, electrolyte is available there. Wiki saying you could use catalyst like Copper or Nickel oxides
while bubbling Cl2 into water. I think it is nonsense, both acids will react with them, sure HCl will!!!!
[Edited on 17-9-2024 by Romix]
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clearly_not_atara
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What you are asking is a violation of thermodynamics. The reaction:
2 Cl2 + 2 H2O << >> O2 + 4 HCl
leans significantly to the left below about 900 C, as determined by the Gibbs energy. You can chlorinate various metals and then hydrolyze the
chlorides. The sequence:
2 Cl2 + 2 MgO >> O2 + 2 MgCl2
MgCl2 + H2O >> MgO + HCl
is thermodynamically favorable at 500 C with removal of the products thanks to Le Chatelier's principle, but it is not exactly easy to run.
Alternatively, HCl can be obtained directly by heating MgCl2 hydrates. This is probably the easiest method to obtain HCl without needing to mess with
chlorine. The decomposition temperature is a little bit on the high side (300 C?) but the process is clean and simple.
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Romix
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Quote: Originally posted by clearly_not_atara  | What you are asking is a violation of thermodynamics. The reaction:
2 Cl2 + 2 H2O << >> O2 + 4 HCl
leans significantly to the left below about 900 C, as determined by the Gibbs energy. You can chlorinate various metals and then hydrolyze the
chlorides. The sequence:
2 Cl2 + 2 MgO >> O2 + 2 MgCl2
MgCl2 + H2O >> MgO + HCl
is thermodynamically favorable at 500 C with removal of the products thanks to Le Chatelier's principle, but it is not exactly easy to run.
Alternatively, HCl can be obtained directly by heating MgCl2 hydrates. This is probably the easiest method to obtain HCl without needing to mess with
chlorine. The decomposition temperature is a little bit on the high side (300 C?) but the process is clean and simple.
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Thank you for your reply Dear, very useful information.
300C+ is like boiling point of H2SO4, would English Quickfit glass handle this temperature increasing it slowly from room temperature or you have no
experience with it, maybe someone else here have?
In case if distillation isn't available, is there any way of decomposing HOCl into HCl, I heard sun lights decomposing it, what are they UV or what?
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averageaussie
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| Quote: Originally posted by Romix | | In case if distillation isn't available, is there any way of decomposing HOCl into HCl, I heard sun lights decomposing it, what are they UV or what?
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The presence of light or transition metal oxides of copper, nickel, or cobalt accelerates the exothermic decomposition into hydrochloric acid and
oxygen
https://en.wikipedia.org/wiki/Hypochlorous_acid#Formation,_s...
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Romix
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Yes, I've read it, not trusting Wiki, proved that lies are written there many times to myself!
Oxides will react with HCl, told it already here! Even if acid will be left, distillation needed to isolate it from all transition metal Chlorides!!!!
Metal anions in acid is no good!
[Edited on 18-9-2024 by Romix]
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averageaussie
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hmm, alright then.
maybe you could evaporate the solution, eventually decomposing the HOCl into HCl and oxygen? HOCl is unstable in solution, you might be able to break
the equilibrium with some heat.
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Romix
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| Quote: Originally posted by averageaussie | hmm, alright then.
maybe you could evaporate the solution, eventually decomposing the HOCl into HCl and oxygen? HOCl is unstable in solution, you might be able to break
the equilibrium with some heat. |
I thought about it, HCl fumes, doubt, all will escape boiling...
With reflux maybe possible.
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Romix
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No testing papers exist for testing concentration of HOCl, even for presence I think none or there is?
There are for Chloride! I have many.
What about testing solution after bubbling lots of Cl2 into it before placing it in a sunny place and few months after, having eye on it, making sure
no one adds acid to it to wind me up.
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averageaussie
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You could probably use an inverted funnel placed underwater to dissolve the gaseous HCl. anything that doesn't get dissolved could be feedback-looped
back in using some cleverly placed tubing.
If I may ask, what do you plan on using the acid for?
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Romix
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| Quote: Originally posted by averageaussie |
You could probably use an inverted funnel placed underwater to dissolve the gaseous HCl. anything that doesn't get dissolved could be feedback-looped
back in using some cleverly placed tubing.
If I may ask, what do you plan on using the acid for? |
Making Potassium Chloride out of plant ash, to convert ammonium nitrate into Potassium salt.
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averageaussie
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| Quote: Originally posted by Romix | No testing papers exist for testing concentration of HOCl, even for presence I think none or there is?
There are for Chloride! I have many.
What about testing solution after bubbling lots of Cl2 into it before placing it in a sunny place and few months after, having eye on it, making sure
no one adds acid to it to wind me up. |
You can find HOCl test strips online pretty easy, and a pool store might also stock them. you could also but the HCl from the pool store too...
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averageaussie
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You can buy potassium chloride, it is sold as a salt substitute.
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Romix
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| Quote: Originally posted by averageaussie | | Quote: Originally posted by Romix | No testing papers exist for testing concentration of HOCl, even for presence I think none or there is?
There are for Chloride! I have many.
What about testing solution after bubbling lots of Cl2 into it before placing it in a sunny place and few months after, having eye on it, making sure
no one adds acid to it to wind me up. |
You can find HOCl test strips online pretty easy, and a pool store might also stock them. you could also but the HCl from the pool store too...
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Where???
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averageaussie
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look up "HOCl Test strips"
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Romix
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Did on Ebay, none there...
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averageaussie
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google. type into a basic search engine "HOCl test strips"
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Romix
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Went through first page of Google search, quoting "HOCl test strips", all sites looking like scam and also very expensive, not risking it!
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averageaussie
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fair enough. you can still buy HCl from a pool store, or better yet, potassium chloride as salt substitute from a grocery store.
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Romix
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| Quote: Originally posted by averageaussie | | fair enough. you can still buy HCl from a pool store, or better yet, potassium chloride as salt substitute from a grocery store.
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Yes, below 10% in UK!
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averageaussie
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the HCl or potassium chloride?
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Romix
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HCl Dear!
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averageaussie
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the hcl being 10% will work just fine for turning the potassium salts into chlorides...
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Romix
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| Quote: Originally posted by Romix | | Quote: Originally posted by averageaussie |
You could probably use an inverted funnel placed underwater to dissolve the gaseous HCl. anything that doesn't get dissolved could be feedback-looped
back in using some cleverly placed tubing.
If I may ask, what do you plan on using the acid for? |
Making Potassium Chloride out of plant ash, to convert ammonium nitrate into Potassium salt. |
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averageaussie
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electrolysis?
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Romix
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Yes, right, until Cathode bottle is filled with concentrated solution of KOH!
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