Sciencemadness Discussion Board - Making Hydrochloric Acid

Making Hydrochloric Acid

darkurza - 3-1-2007 at 21:00

Source Wikipedia and Various Google sites.

If I wanted to make Hydrochloric Acid (HCl) at home, could I do it with these 2 methods?

Method 1:
Dissolved the right amount of Salt (NaCl) into Distilled water (H20) to not have other contaminants. Cut the wires of a cell phone charger and shave the insulation off at the tips so it acts as an electrical source. Tape the wires in a glass jar and connect a piezoelectric igniter into the jar. Fill it up with NaCl H2O and place a cork and a tube on. Plug the cell phone charger in.

electricity
NaCl + H2O -----------> NaOH + Cl2 + H2

In theory, this should cause Sodium Hydroxide (NaOH) to form at either the cathode or the anode and Hydrogen (H2) and Chlorine (Cl2) gas should bubble out. Use the tube and some method of draining the sodium hydroxide and salt and water solution and refill the jar with H2O. Then, use the piezoelectric igniter to combine the two gases and dissolve it in water making weak hydrochloric acid. Boil it to get rid of some water and concetrate it.

Method 2.

Get a large wine bottle and fill it up with bleach and an acid (Vinegar, Concentrated Lemon Juice). This should create small amounts of Chlorine gas. Cover the bottle with a syringe and pump out the Chlorine. Next, attach a tube to the syringe and slowly bubble it into a large solution of ammonia. According to Wikipedia, Chlorine catches on fire when passed through ammonia and Nitrogen Gas and Hydrochloric Acid is created. Unless there is a lot of ammonia, Nitrogen Trichloride (NCl3), a dangerous and useless explosive is also created.

Will this work and is there anything wrong with my plans?

guy - 3-1-2007 at 21:04

H2 and Cl2 will explode when ignited or even when exposed to sunlight. There's already a thread on this.

darkurza - 3-1-2007 at 21:43

Quote:

Originally posted by guy
H2 and Cl2 will explode when ignited or even when exposed to sunlight. There's already a thread on this.

I assume doing it in small amounts would lead to smaller explosions that are safe. Sort of like this http://mattson.creighton.edu/Cl2/Photo121.jpeg

Is there anything wrong with my methods of making this? And can you link me to the thread, I'm new here.

al - 10-1-2007 at 11:02

It exists other simple way to produce HCl (and even HF) :

Use a 2 liter ceramic flask with two holes : one up to put the matter and one on the side to evacuate HCl.
Put in the flask siilica (powder of sand) and NaCl (common salt) and heat strongly (500°C to 700°C). If you do not get HCl, add a small amount of the mixture silica-water. You should get HCl , collect it in cold water.

The chemical reaction is : SiO2 + H2O + 2 NaCl ------> SiO3Na2 + 2 HCl

Centuries ago people used to prepare HCl using this method.

The interesting point is that you only need very common products.

The hard point is the making of the flask : alternative way is to use a steel cooker , the same some people use to distillate ethanol. Copper is better.

To get HF from fluorite :

SiO2 + H2O + 2 HF ------> SiO3Ca + 2 HF

YT2095 - 10-1-2007 at 11:13

silicon dioxide water and table salt!?

I assume this must be a VERY strong vessel to take water at 700c!

Aqua_Fortis_100% - 10-1-2007 at 13:05

Quote:

Put in the flask siilica (powder of sand) and NaCl (common salt) and heat strongly (500°C to 700°C).

this looks interesting.. but i'm not sure about this, because the MP of NaCl is about 801°C..(is the melt phase of NaCl required for react (better?) with the SiO2????? or both reactants need to be melted?)..
if it's true (500°C - 700°C), i can use this to raise the conc. of my 10% HCl, simple bubbling the HCl gas into the cooled 10% HCl..

but about the heat source: can i use wood to provide the fire? (about 600°C)
thanks..

Mental_sam - 10-1-2007 at 14:44

Is this worth it when you can purchase for 85$ /25ltrs from your local swiming pool shop ???

asilentbob - 11-1-2007 at 00:51

You can indeed buy it for quite a reasonable price.

Boiling a hydrochloric acid solution will release a good deal of the dissolved HCl, its like an ammonia solution, ammonia dissolved in water. Cooling the solution down and passing more HCl into it will concentrate it.

H2SO4(l) + NaCl(s) --heat--> NaHSO4(s) + HCl(g)
HCl(g) + H2O(l) (very cold water)---> HCl(aq)
Would be a decent way to do it assuming you can fashion an appropriate apparatus. You also get the NaHSO4 that you can use for other experiments. However, i wouldn't try to make it. I would just buy it. If you happen to form it as a by product though by all means dissolve it in water to recycle it and be kind to the enviroment.

A hydrometer to test your concentration or doing a titration would be a good idea if your going to be using the hydrochloric acid.

al - 11-1-2007 at 00:58

Well, you will found this recipe to make HCl in old chemistry books. People prepared HCl in a retort heated to redness. Even Basile Valentin describes the method.

To know precisely about the reaction you may compute the constant K of the reaction :

SiO2 + H2O + 2 NaCl ------> SiO3Na2 + 2 HCl

Delta H = - RT log K

with Delta H = enthalpie of the reaction.

Delta H = Delta SiO2 + Delta H2O + 2 Delta NaCl - (Delta SiO3Na2 + 2 Delta HCl)

Of course take into account the temperature .

Melting of NaCl is not necessary.

I put the quote of the english chemistry book of my site :

http://albert.cau.free.fr/English/Chemicals.html

Aqua_Fortis_100% - 11-1-2007 at 07:59

Quote:

originally posted by YT2095 :
I assume this must be a VERY strong vessel to take water at 700c!

Tim, yes... only now i noticed also about water..
BAH!

so, al , how you make this procedure ? you add water in small fluxes slowly on the NaCl/SiO2 at 500-700°C ???

Quote:

originally posted by Mental_sam :
Is this worth it when you can purchase for 85$ /25ltrs from your local swiming pool shop ???

unfortunatelly i never found this here (in local swiming pool shop) because the most used (here) Ph-regulator is H3PO4...

[Editado em 11-1-2007 por Aqua_Fortis_100%]

al - 11-1-2007 at 08:33

Well ,

Use a retort with an extra hole in the top.
Put NaCl and silica in the retort and heat to redness.
NaCl which contains a lot a water will dry
Then add small portions of a kind of mud made with silica and water
NaCl produce HCl.

Other old recipe was the heating of NaCl with alun (you may get the product in chinese stores)

Aqua_Fortis_100% - 11-1-2007 at 08:59

Thanks,al , but about the heat source, wood work fine? ( i have virtually TONS of this in my yard).

Quote:

Other old recipe was the heating of NaCl with alun (you may get the product in chinese stores)

what is this "alun", can you give more details???

thanks.

[Editado em 11-1-2007 por Aqua_Fortis_100%]

darkurza - 11-1-2007 at 19:39

Quote:

Originally posted by al
It exists other simple way to produce HCl (and even HF) :

Use a 2 liter ceramic flask with two holes : one up to put the matter and one on the side to evacuate HCl.
Put in the flask siilica (powder of sand) and NaCl (common salt) and heat strongly (500°C to 700°C). If you do not get HCl, add a small amount of the mixture silica-water. You should get HCl , collect it in cold water.

The chemical reaction is : SiO2 + H2O + 2 NaCl ------> SiO3Na2 + 2 HCl

Centuries ago people used to prepare HCl using this method.

The interesting point is that you only need very common products.

The hard point is the making of the flask : alternative way is to use a steel cooker , the same some people use to distillate ethanol. Copper is better.

To get HF from fluorite :

SiO2 + H2O + 2 HF ------> SiO3Ca + 2 HF

Seems like an interesting method. I will try it once I find a fuel to burn at 800°C. Anyone suggestions? I was thinking of using zippo fluid but I'm not sure the temperature of that. I plan to place a beer bottle with a tube in a cork filled with sand, salt and water into a larger jar (miracle whip jar). Then pour the fuel into the larger jar and ignite the fuel and just wait. I assume HCl(g) will come out of the tube...

12AX7 - 11-1-2007 at 20:26

Ehh beer bottle? Ah no, you're making glass here, not gonna happen! Copper is a stretch! Heavy steel or better yet, corrosion-resistant alumina, mullite (and other ceramics) or inconel, monel (probably), etc.

There's no way silica is acidic enough with liquid water around to decompose salt. Possibly in an autoclave (where "liquid water" is pushing the definition of "liquid"). Steam passed through a ceramic retort charged with molten salt and sand may produce the desired result.

Phosphoric and sulfuric are both "refractory" enough to produce HCl with ease without resorting to stronger glass formers such as SiO2 or B2O3.

Tim

al - 12-1-2007 at 00:37

Alun is potassium sulfate extracted from leaching of some rocks. This compound was very used centuries ago as a basic material to produce nitric and hydrochloric acids.

The old process to get HCl and even HF may be modified today. A retort is not necessary, you may use a tube of refractory material, inside put SiO2 and NaCl , when the tube get redness, so send a stream of H2O vapor and collect at the output HCl in cold water.
The reaction works easily with fluorite (CaF2).

Reaction occurs because sodium or calcium silicate is produced, moreover thermodynamical considerations, as well as experiments, demonstrate the feasibility of the reaction.

I am working on getting sulfuric acid from plaster of Paris (CaSO4) : CaS , then H2S , then S , then SO2, S03.

al - 12-1-2007 at 00:52

Heating at high temperature.

With gas the temperature depends on the flow of gas and a good "thermal insulation" : my gas oven is able to melt silver , gold and copper.

I saw people in mexico using used car oil and a compressor to melt aluminium : a hole in the ground, they put a tube for compressed air and a tube for oil. To start the fire, they use some pieces of wood , then they send the oil and start the compressor . After they put the big crucible above

darkurza - 12-1-2007 at 04:57

Aluminum melts at 600°C. Butane from a lighter is suppose to burn at 700.

Daddy - 8-4-2009 at 07:42

This thread got my attention since short ago my wife has been warned that sale of muriatic acid will soon be forbidden in this country, and I do not like storing up larger quantities of chemicals. So it would be great to make it by myself; but methods requiring high temperatures and very special vessels are currently out of my reach.

So I am getting back to the method proposed at the beginning of this thread (electrolyzing NaCl and reacting Cl2 with H2): is there a safe way to make these gasses react? For example doing it slowly in small quantities, maybe just at the rate at which the gasses are produced by the electrolysis?

And another intriguing question: anybody knows how the human body synthesizes HCl? I can hardly imagine our body producing sulphuric acid as a first step; not to speak of elemental chlorine and hydrogen. But how then is it done?
- A first thought: maybe via phosphoric acid? I just found this on Wikipedia:
NaCl(s) + H3PO4(l) -> NaH2PO4(s) + HCl(g)

(just being confused about the (l) where I would expect (aq): does this mean the acid has to be pure and melted? Then it would not be possible inside the human body...)

And I think phosphoric acid can be prepared from fertilizer containing phosphates? I have to investigate more about this...

Globey - 8-4-2009 at 07:59

Loperamide and Styrofoam will be next. Hey don't laugh...they will cut WAY down on PS based stuffs in guise of some environmental concerns. I think PPA was dealt away with because of FDA “worries” over the possibility that if you ate a handful of it, you might have a .000001% increased chance of having a premature stroke. Just a little exaggeration, but ya get the point. Still, I detect a subtle aire of arrogance and face saving when authorities move slow to classify something which has been ubiquitously around. Not just because of the negative effects of denying it into legit commerce, but because in doing so, they are also tacitly admitting "hey, we were wrong all along, we shouldn't have had this stuff available OTC". Merck index is also very reluctant to sometimes change fundamental information when new, more accurate information comes to light. They are slow to acknowledge, or will simply omit the entry all together. Or sometimes they will stubbornly keep the mistake in, and dig in their heels, feigning passion like a lying lawyer who says "I take great umberage to that!".

OOPS where was I.

bquirky - 8-4-2009 at 08:22

Ive not tried it but i had been under the impression that electrolising salt water with a split cell and a porous membrane (like the old clay pot in another container) whould create a solution of HCL on one side and solution of NaOH on the other.. has anyone done this and gotten a result ?

Assuming you can only generate a fairly dilute solution of HCL you may be able to upgrade it by heating one sealed vesle of the dilute solution and bubling it through a smaller volume of cold water.

if you can make that work well and the tards ban it you might be able to make a killing on the illegal black HCL market

sakshaug007 - 9-4-2009 at 22:10

Hey everyone,

Just so you know there are two threads that have already gone into this pretty in depth, here they are:

http://www.sciencemadness.org/talk/viewthread.php?tid=11954

http://www.sciencemadness.org/talk/viewthread.php?tid=2154&a...

Hope this helps

UnintentionalChaos - 9-4-2009 at 22:44

Quote: Originally posted by bquirky

Ive not tried it but i had been under the impression that electrolising salt water with a split cell and a porous membrane (like the old clay pot in another container) whould create a solution of HCL on one side and solution of NaOH on the other.. has anyone done this and gotten a result ?

Assuming you can only generate a fairly dilute solution of HCL you may be able to upgrade it by heating one sealed vesle of the dilute solution and bubling it through a smaller volume of cold water.

if you can make that work well and the tards ban it you might be able to make a killing on the illegal black HCL market

*blinks* Please learn something about electrochemistry. *coughredoxcough*

DJF90 - 9-4-2009 at 22:51

@bquirky - The sodium ions would head towards the anode, the chlorine ions would head towards the cathode. At the anode, hydrogen is produced (Na is formed which INSTANTLY reacts with the water to form hydrogen and sodium hydroxide) and at the cathode, Chlorine is produced (due to oxidation of 2Cl- => Cl2) There is NO HCl formed (unless you want to take the H2 and Cl2 gases and react them, like I believe may have been mentioned up thread.

woelen - 9-4-2009 at 23:11

DJF90, you mistakenly exchange anode and cathode. Hydrogen is formed at the cathode (-) and chlorine is formed at the anode (+).

@Daddy: This is not a suitable way of making HCl, unless you are VERY patient. Keep in mind that electrolysis is a slow process. Very roughly speaking, at a current of a little more than 1 A you only have one mol of electrons every 24 hour day (for exact numbers, please lookup constant of Faraday). To produce one mol of H2 and one mol of Cl2 you need 2 mols of electrons. This gives 2 mols of HCl. So, for one mol of HCl you need one day of electrolysing at 1 A. If you dissolve 1 mol of HCl in 1 liter of water, you get acid of appr. 3% concentration.

There are many practical problems as well. You need a graphite anode. But this anode quickly corrodes, it pulverises. Another issue is that chlorine dissolves in the liquid fairly well (this makes it possible to make hypochlorite and chlorate by means of electrolysis). The final issue is how to handle the voluminous chlorine gas and hydrogen gas and have them react with each other in a controlled way and get the reaction product dissolved in water without contamination with chlorine.

garage chemist - 10-4-2009 at 02:04

Heating NaHSO4 with NaCl (in a test tube or flask) is probably the easiest OTC method for HCl production.
I my old chemistry set this reaction was used multiple times to generate HCl gas for experiments, like the HCl fountain which demonstrates how vigorously water absorbs gaseous HCl.

Saerynide - 10-4-2009 at 03:28

Quote: Originally posted by bquirky

I tried this many times years ago. Tried the clay pot, paper towel salt bridge, and aquarium tubing stuffed with polyester. The NaOH solution is incredibly dilute, and Cl2 is generated, not HCl.

Dissolving the Cl2 in very cold water does not really yield HCl, but just water with a shitload of Cl2 in it. When the solution warms up, ALL the Cl2 will be released. This is how I got poisoned. Took months to get better. Please don't do it.

Elawr - 10-4-2009 at 22:15

Quote:

....And another intriguing question: anybody knows how the human body synthesizes HCl? I can hardly imagine our body producing sulphuric acid as a first step; not to speak of elemental chlorine and hydrogen. But how then is it done? ....

In our bodies HCl is generated by gastric parietal cells using a subcellular organelle called a proton pump. This is a structure that spans the mitochondrial membrane, creating a channel through which individual protons are selectively moved. The hydrolysis of ATP to ADP provides energy to drive a conformational change within the proton pump which forces protons through. An excess of protons outside the mitochondria results, creating an electrochemical gradient that moves chloride ions passively across the gap through another specific channel.

The mechanism is sufficiently robust that pH levels as low as around 2 are attained for gastric juice, before being transported out of the cell into the gastric secretory ducts.

Pretty strong stuff stomach acid is!

[Edited on 11-4-2009 by Elawr]

Daddy - 11-4-2009 at 07:31

This is very interesting. So our body is still much more "advanced" technology than our laboratories!

Quote:

Heating NaHSO4 with NaCl (in a test tube or flask) is probably the easiest OTC method for HCl production.

... but in order to produce NaHSO4 I would still need sulphuric acid, wouldn't I? Or how else could I obtain it?

- Somebody has tried with phosphoric acid? (I have not so much time for experiments, but once I find out how to make phosphoric acid, I might try it.)

hissingnoise - 11-4-2009 at 08:16

Sulphuric acid will react with NaCl at RT; heat is needed only when the initial vigorous reaction subsides.
If you can get H2SO4 draincleaner you don't need bisulphate. . .

[Edited on 11-4-2009 by hissingnoise]

woelen - 11-4-2009 at 09:19

In a place where HCl will be taken off the shelves, conc. H2SO4 certainly will not be available. So, I'm afraid this method is not of any use for Daddy. The method, suggested by garage chemist with NaHSO4 indeed is the best one. I tried this as well and it works quite well. You only need to use some excess NaHSO4 and need to provide sufficient heat. NaHSO4 (pH-minus for swimming pools) melts fairly easily. You can do this in a metal vessel. The vessel certainly will corrode, but the HCl still is pure, all contamination will remain behind in the vessel.

hissingnoise - 11-4-2009 at 10:14

It's hard to see how the PTB could justify outlawing HCl for cleaning masonry or H2SO4 for unblocking drains---but if Daddy was really stuck he could surely get battery acid and boil that down---failing that there's always the volcanos.
OK, that's not really serious---lugging filled carboys down a steep cone might be heavy exertion.
But then, there's always coca leaves. . .

JohnWW - 12-4-2009 at 13:38

HCl is commonly industrially produced as a byproduct of chlorination reactions; for example, the chlorination of slaked lime, Ca(OH)2, to obtain "chloride of lime" used as a swimming-pool disinfectant; and chlorinations of hydrocarbons to produce chlorinated hydrocarbons for various purposes, e.g. vinyl chloride used to make PVC, and chlorocarbon insecticides although these are now banned for agricultural use.

Daddy - 14-4-2009 at 12:40

Quote:

but if Daddy was really stuck he could surely get battery acid and boil that down

yes, that was the only way I was able to obtain H2SO4... now, I have still a bottle of HCl in stock and I am not using a lot, so it is not that urgent.

I was just curious about the alternative with phosphoric acid, and I have not a lot of experience, but I would be interested to know if someone has tried that.

hissingnoise - 14-4-2009 at 13:41

Yes, you can do it with phosphoric acid, but heating may be necessary to start the reaction.
If getting phosphoric is easy for you, your problem is solved. . .
Making H3PO4 is a different story, though!

woelen - 15-4-2009 at 00:10

Yes, with H3PO4 it actually is very simple. First boil down the H3PO4, such that it becomes concentrated. Keep on boiling, until the temperature of the liquid goes well above 100 C (e.g. 130 C). Then stop boiling. You should not go further, as that makes glassy and syruppy derivatives of phosphoric acid like pyrophosphoric acid and metaphosphoric acid.

To the acid you add solid NaCl and then you carefully heat. Gaseous HCl escapes and this can be dissolved in water by putting an inverted funnel just a few mm below the surface of the water and leading the HCl gas to this funnel through a flexible tube. In this way you can also make HBr.

Do the heating of the phosphoric acid in a metal can, not in good glassware. Hot concentrated phosphoric acid slowly attacks glassware. So, use old glassware which may become matte/milky, or use some throw-away metal can.

chief - 15-4-2009 at 02:40

There's no way around electrolyzing Na2SO4, from some starting-batch of H2SO4 and NaCl ;
:: then by electrolysis : Na2SO4 ==> H2SO4 + NaOH
:: H2SO4 + cheap NaCl ==> more HCl and Na2SO4, etc.

Also worth implementing because of the constant souce of NaOH. Maybe the electrodes for this don't have to be as good as for the chlorate cell ; eg. Pb as anode should do, and stainless steel as kathode _will_ do.

hissingnoise - 15-4-2009 at 03:19

I hope I haven't misread your post chief, but electrolysis of Na2SO4 does not produce H2SO4 + NaOH, if that's what you're suggesting. . .

nitric - 15-4-2009 at 08:45

the home method for those without H2SO4 is to use NaHSO4 + NaCl --> HCl + Na2SO4

DJF90 - 15-4-2009 at 10:11

woelen: I apologise, I should have checked my electrodes before posting.

nitric: If you cared to read the thread then you'll see this was covered by garage chemist in the last post of the first page. With this hobby there is often more than one way to skin a cat, as it were, so saying "the home method for" this or that is often only one of many, which may or may not be appropriate depending upon the resources of the individual members.

nitric - 15-4-2009 at 13:45

oh sorry, i've just didn't have the patience to read it all, i've just seen this method a lot for easy, OTC, HCl

DJF90 - 15-4-2009 at 15:59

Any HCl formed would instantly react with the carbonate. You said yourself that the Gibb's free energy is positive over most temperatures...

sakshaug007 - 15-4-2009 at 16:41

Quote: Originally posted by DJF90

Any HCl formed would instantly react with the carbonate. You said yourself that the Gibb's free energy is positive over most temperatures...

Oh carbonate duh. lol!

Thanks

"Think before you type.."

DJF90 - 15-4-2009 at 18:59

We all do it sometimes. I've always wandered how easy it would be to control the reaction between hydrogen and chlorine gases... I'm sure I read somewhere that the reaction can be explosively fast.

Saerynide - 15-4-2009 at 21:38

I was always under the impression that the reaction occurs exhorably slowly without UV light, but once UV hits it, it pretty much explodes.

chief - 16-4-2009 at 01:24

@hissingnoise" Wasn't there a thread by "der alte", where he did exacly that ? With a diaphragma, of course ... .

What else would one expect from electrolysis of Na2SO4 ??? The NaHSO4, although available even here in germany, must always be bought (6-7 EUR/kg), while a set-up electrolytic cell can just be used ever again ...

hissingnoise - 16-4-2009 at 04:02

I haven't seen it, chief; if I had I'd be real excited.
H2SO4 and NaOH by electrolysis would be breakthrough-stuff, surely?
Am I still missing something here?

chief - 16-4-2009 at 08:20

Where's the problem ?
==> SO4(2-) goes to the anode, reacting with water to H2SO4
==> menawhile 2Na+ go to the Kathode, givin NaOH
Without a diaphragma both then can react again, to Na2SO4 + H2O ; but with a diaphragma ....

Same possible for many other acids from their salts ...

"Der Alte" really tried this, is described in some H2SO4-manufacturing thread ; so the H2SO4 can forever be recycled, and just reacted with fresh NaCl each time for new HCl ; NaCl in ==> HCl + NaOH out.

In industry there are more efficient ways to produce each of the compounds, on the larger scale ...

[Edited on 16-4-2009 by chief]

hissingnoise - 16-4-2009 at 10:00

You're right chief, I found DerAlte's thread, I posted on it myself (absentmindedly), but it's impractical as the conc. afforded was only 20%---way too dilute and the process, IIRC seriously energetically inefficient.
Using that process would be frustrating in the extreme. . .

chief - 17-4-2009 at 03:43

Only 20 %, but that doesn't matter in this case:
==> HCl-gas has some solubility, which decreases with temperature, so some of it may be gassed out even from a dilute solution like that, which would stem from reacting such a 20 %-Solution with NaCl
==> since the wanted educt is a gas, HCl, it doesn't matter if the H2SO4 is impure and contains any salts etc.
==> alls the salts in solution are part of the process, and can be left there

So at most, depending on the HCl-solubility, the 20% H2SO4 would at most have to be concentrated to 40 % or something like that.
Also: Since the purity of the H2SO4 plays no role, the conc. of it may be driven up way higher ; "der alte" surely hat to consider the end-purity of the H2SO4 in his process, but for making HCl it plays no role.

And finally: The energetic efficiency may be not too bad when compared to having to buy any chemicals ; also: Will it be worse than with the more complicated chlorate-production ? H2SO4 from a salt is only a electrolytic separation, not such a complicated oxidation like with the chlorate ... ; and even on the chlorate it's agreed upon that making it oneself is economically competitive ...

chief - 17-4-2009 at 04:36

Well, second thought about it: Maybe after a while of electyrolyzing/ reusing the H2SO4-brine there would be some buildup of HClO3 or HClO4 ...

HydroCarbon - 19-4-2009 at 20:23

Quote: Originally posted by Elawr

The mechanism is sufficiently robust that pH levels as low as around 2 are attained for gastric juice, before being transported out of the cell into the gastric secretory ducts.

Pretty strong stuff stomach acid is!

[Edited on 11-4-2009 by Elawr]

Perhaps it could be extracted from puke?

Daddy - 9-5-2009 at 09:36

I am back again... I did not yet try to actually make HCl. But in the meantime I pursued the idea of making phosphoric acid from fertilizer and wrote about the result in another thread whih is already covering this issue:

http://www.sciencemadness.org/talk/viewthread.php?tid=7370#p...

(I got at least *some kind of* phosphoric acid, but I am afraid it is not H3PO4.)

Here is another alternative I found in a book:

H2S + Cl2 = 2 HCl + S

If I understood correctly, this reaction is "silent", not like H2 + Cl2. H2S could be made by heating paraffin together with sulphur - so no acid would be needed during the process -, and the sulphur would be regenerated by the reaction. Only that I do not like the idea of making so many ugly gasses at a time, so I am not sure if I ever want to try this out.

Magpie - 9-5-2009 at 09:45

Quote:

Only that I do not like the idea of making so many ugly gasses at a time, so I am not sure if I ever want to try this out.

H2S is not only ugly it is deadly. One member here had a narrow escape from it.