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Author: Subject: Hydrogen chloride gas balloon
wireshark
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[*] posted on 18-3-2013 at 23:58
Hydrogen chloride gas balloon


I know hydrogen balloons are a regular thing used in labs. But what about HCl? I want to make hydrochloric acid and I don't have very much equipment at the moment for a proper generator/bubbler apparatus.

So how about filling a balloon with HCl (stoichiometric amount), putting it over a flask with water (stoichiometric amount) and a stirbar, and then letting it go for a day or so. All done outside. Is this safe? Would it work?
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kristofvagyok
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[*] posted on 19-3-2013 at 00:35


Quote: Originally posted by wireshark  
Is this safe? Would it work?

Yes, yes.

Just don't breathe it in.




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zed
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[*] posted on 19-3-2013 at 13:57


No, no, no. Buy, or make, better equipment.

Also, are you assuming that a common balloon will be resistant to HCl gas?

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[*] posted on 19-3-2013 at 14:05


Hydrogen chloride is very soluble in water so even a small amount might result in rapid deflation as the gas reacts to form hydrochloric acid.
If you connect a balloon filled with hydrogen chloride to a flask containing water it will deflate almost instantly.
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wireshark
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[*] posted on 19-3-2013 at 19:50


Quote:
Hydrogen chloride is very soluble in water so even a small amount might result in rapid deflation as the gas reacts to form hydrochloric acid.
If you connect a balloon filled with hydrogen chloride to a flask containing water it will deflate almost instantly.


All right, what's wrong with that? Will the acid shoot back up into the balloon because of the pressure difference? If so, I could pinch it off before the balloon deflates.

Quote:
No, no, no. Buy, or make, better equipment.

Also, are you assuming that a common balloon will be resistant to HCl gas?


It's not like I'd use the same balloon more than one or two times. Let's say the balloon is made of polyethylene or polystyrene--there's no alkene to attack. What'd happen anyway?
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[*] posted on 19-3-2013 at 20:12


Simple enough to just test it out, and stop postulating.
Go outside on a slightly breezy day. Don some goggles and maybe some gloves or apron if your paranoid. Put some salt into the bottom of a flask, add a bit of H2SO4 and cap it with the balloon. Once the balloon is filled (if it doesnt damage and pop) take it off, and transfer it to the top of a flask filled with chilled, stirred water. The HCl will be desolved fast and the bolloon will likely deflate fast, as SS mentioned. This is no problem, and could probably make a good demo of gasses dissolving in water.

Seems like a safe, easy, and cheap experiment. Just don't deeply inhale and whiff it or dump it in your eyes and you should be fine. Get to it! ;)

EDIT: Just place a small HCl generator and a wide mouthed container of ice water into a tupperware contianer. The cold water will absorb much of the released HCl pretty quickly. Just let it sot overnight, and then titrate the newly formed HCl(aq) to get a concentration. then record data and manipulate variables to optimize your proceedure.

Or rig a gas gen, piping, a suckback trap, inverted funnel, and cold water filled reciever. I think you may be over complicating how to throw this together. Easy peasy.

[Edited on 20-3-2013 by Bot0nist]




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[*] posted on 19-3-2013 at 22:24


Quote: Originally posted by wireshark  
I know hydrogen balloons are a regular thing used in labs. But what about HCl? I want to make hydrochloric acid and I don't have very much equipment at the moment for a proper generator/bubbler apparatus.

So how about filling a balloon with HCl (stoichiometric amount), putting it over a flask with water (stoichiometric amount) and a stirbar, and then letting it go for a day or so. All done outside. Is this safe? Would it work?


Add concentrated sulfuric acid to NaCl to get HCl......

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[*] posted on 21-3-2013 at 15:02


Better is H2 (non-toxic, non-corrosive, does not react with water, easy to prepare and a lighter gas).

Downsize, if mixed with air and ignited, will explode. Also, the H2 is very probe to escape from sealed containers.

[Edited on 21-3-2013 by AJKOER]
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[*] posted on 22-3-2013 at 07:20


I remember seeing a youtube video.

They fill a long graduated cylinder with chlorine. The chlorine comes from a cylinder.
They also have a hydrogen cylinder. They light up the hydrogen to have a large ongoing flame. They insert it into the chlorine. It burns in the chlorine but with a pinkish color.

Then, they put the graduated cylinder in water and boom, the water gushes up. Sort like the ammonia fountain experiment.
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[*] posted on 9-6-2015 at 07:24


I would also need HCl in a balloon, but it seems to me that the sulfuric refuses to react with NaCl. I mean, it does, but vast majority of the NaCl refuses to dissolve (in 37% H2SO4) and there is virtually no gas escape even upon heating. How the heck should I do that?



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[*] posted on 9-6-2015 at 08:09


Quote: Originally posted by Adas  
I would also need HCl in a balloon, but it seems to me that the sulfuric refuses to react with NaCl. I mean, it does, but vast majority of the NaCl refuses to dissolve (in 37% H2SO4) and there is virtually no gas escape even upon heating. How the heck should I do that?


Only concentrated H2SO4 (98 % or better) will displace the HCl.

HCl and H2SO4 are both very strong acids.

In NaCl(s) + H2SO4(l, >98 %) < === > NaHSO4(s) + HCl(g) the reaction equilibrium is pushed to the right because of the escaping HCl gas.

Fusing NaCl with NaHSO4 (sodium bisulphate, pool supplies) should also work but requires heat:

NaCl + NaHSO4 === > Na2SO4 + HCl(g)

There are plenty of HCl generator experiments on this forum. Search and yee shall findeth.

[Edited on 9-6-2015 by blogfast25]




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[*] posted on 9-6-2015 at 08:35


Oh, I have plenty NaHSO4. I might try that, thanks for your helpful response. :) I hope they will melt together as expected.



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[*] posted on 9-6-2015 at 09:02


Quote: Originally posted by Adas  
Oh, I have plenty NaHSO4. I might try that, thanks for your helpful response. :) I hope they will melt together as expected.


Anhydrous would be best. Tell the difference from the monohydrate by its MP. Mix the salts intimately, using an excess of NaCl (it prevents the bisulphate from fuming off small amounts of SO3)




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[*] posted on 9-6-2015 at 09:49


So, to summarize... You decided to fill a balloon with hydrogen chloride gas because you aren't comfortable/equipped to use the lab technique, but running a thermal decomposition reaction so hot that it is generally done with a blowtorch or related gas powered flame, that's a piece of cake?

Cool.
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[*] posted on 9-6-2015 at 13:09


Well, back to answer the OP.

Yes, it would work if it were absolutely necessary, and there were no other possibilities.

Stick the reagents in the balloon itself (small quantity only - do the maths).

Seal the neck of the balloon onto the test tube, or whatever holds the water.

Have the whole thing in a plastic tray, such as the bottom cut off a 5 Litre plastic milk jug (in case the balloon bursts) and the entire operation must done Outside.

With HCl a stirbar will not make much difference.




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[*] posted on 11-6-2015 at 07:09


The balloon will fall to the ground...
HCl weights 36.5g/mole thus as a gas 36.5g/22.41 Liter

O2 weights 32g/mol --> 32g/22.41L
N2 weights 28g/mol --> 28g/22.41L
Air is 1/5 O2 and 4/5 N2 --> 32/5+28*4/5 = 28.8g/22.41L

So HCl gas is denser than air, with the extra weight of the balloon --> fast landing.

The rubber of the balloon will not stand long HCl especially if there is some humidity in the air.

[Edited on 11-6-2015 by PHILOU Zrealone]




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[*] posted on 11-6-2015 at 09:11


Quote: Originally posted by PHILOU Zrealone  

The rubber of the balloon will not stand long HCl especially if there is some humidity in the air.



It wouldn't HAVE to be made of latex rubber: an inflatable beach ball (pPVC, I think) would resist even wet HCl quite well.




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[*] posted on 26-6-2015 at 02:08


The method with NaHSO4 and NaCl works quite well when you don't need massive amounts. I used a teflon tube which I glued to the piece of balloon that has a hole in it.. to make it airtight. It's okay but the glue I've used falls apart very quickly. Already ordered some sillicon stoppers with holes, I hope they could withstand that.



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[*] posted on 8-7-2015 at 12:22


Also, is there any chance this could work with bromides too? Or is NaHSO4 not acidic enough for that? Would bromides eat silicone stoppers?



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[*] posted on 8-7-2015 at 14:03


If you have the ability to generate bromine gas, try it out and then tell us what happens.

Simple stoichemitry and ideal gas law will allow you to calculate the volume of gas you produce to keep it at a safe level.

Work out the maths along woth the testing procedure you propose and then post your calculations here.

People will check them for you.

You'll get more help here if you actually do some work for yourself.




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[*] posted on 9-7-2015 at 00:44


I don't get it. I'm not even talking about bromine, but HBr gas. I don't know how to calculate whether NaHSO4 and NaBr would react well. Even if there are some pKa values available, this is of little practical importance as chemistry is really weird sometimes (most of the time). I merely expected someone with actual practical experience to respond to my post.

Also I don't have NaBr to test this myself, and serious information about silicone resistance to HBr can not be found online. I've just found one paper that states that hydrogen chloride gas does the same damage to it as methane. Yes, METHANE. And it didn't say "no damage", it was more like "pretty serious damage". Definitely unreliable.




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