Talk:Hydrochloric acid

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This is article became FA on 2005-04-08, the first big effort of WP:Chem. Wim van Dorst (Talk) 20:33, 28 January 2007 (UTC).
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Contents

[edit] What is the pH of Hydrochloric acid?

I couldn't find it in the article.

Like any other acid, the pH depends on the concentration. It can be anywhere from 7 to -2 or so. --Carnildo 21:19, 8 Apr 2005 (UTC)
For the common concentrations, it is in the table now. Obviously, if you dilute it more, pH increase up to (max) 7. Lowest is about -1.1, as shown in the table. Wim van Dorst 22:15, 2005 Apr 8 (UTC).

For every tenfold dilution the pH goes up by 1 pH unit until you come close to pH 7. Cacycle 22:54, 8 Apr 2005 (UTC)

What about pure HCl?

Does not have a pH at all. Cacycle 08:55, 9 Apr 2005 (UTC)

i.e., if you have pure hydrogen chloride gas, there is no water, and the definition of pH requires water. If you mean what is the pKa, I see that the hydrogen chloride page lists this as -4. Walkerma 21:46, 9 Apr 2005 (UTC)

Doesn't acid need to be aqueous to be, well acidic, anyway? Isn't HCl in non aqueous form, well, non-reactive? Hydrogen chloride? -- Natalinasmpf 06:01, 25 Apr 2005 (UTC)

Yes, it does need to be aqueous to have a pH, per the definition of the pH. But HCl in pure form is also very reactive. Wim van Dorst 12:35, 2005 Apr 25 (UTC).

Yes, but that only happens when its mixed with organic material, because they organic molecules are bound to contain oxygen and hydrogen to create an immediate ionisation effect - forming the same negative chlorine ion and the positive ion of the other side of the molecule. Which is the key to hydrochloric acid's corrosiveness. Hydrogen chloride won't corrode metals by itself, unless you decided to add some sort of organic/water molecule to it. Which is the key difference with the disassociation effect, thus has less oppurtunies to corrode. Because from what I see, hydrogen chloride only reacts when it reacts with an organic molecule/water and becomes hydrochloric acid; it has to make that transformation. It still isn't corrosive by itself. -- Natalinasmpf 18:28, 26 Apr 2005 (UTC)

Okay, you guys have me confused. I recently took a chemistry class at one of the top colleges in the United States. There, we supposedly had and worked with "pure molar" Hydrochloric Acid, listed at somewhere around 16. Obviously, if Hydrochloric Acid is a solution and therefore a homogenous mixture in a water solvent, it could not be listed as pure from a molar aspect. However, we were never given a pH, and the molar scale is generally considered more accurate. Can anyone help me out with my confusion?207.118.41.6 06:06, 20 May 2007 (UTC)

There is no such thing as "pure molar" hydrochloric acid. 100% (anhydrous) "hydrochloric acid" is actually hydrogen chloride gas, a distinct chemical. The dissolution of hydrogen chloride in water produces hydrochloric acid, in the same manner that the dissolution of sodium chloride in water produces salt water. Hydrochloric acid is typically stored at a maximum concentration of about 38% (w/v), as it isn't very stable above that concentration (too much of it vaporizes to make it practical or safe for use). Acid solutions aren't typically measured by pH, because it is not nearly as accurate or easy to measure as other units (mass and volume for molarity). However, as a reference, 3.647% (w/v) or 1M hydrochloric acid has a pH of 0.0. Remember that "pure" can just as easily imply "free of contaminants" as it can "100%" - as to why your professors or TAs chose to label something as "pure molar," I am unsure, because it should have been labeled with a quantitative value for molarity or w/v percentage. Hope this helps! Dcteas17 06:52, 20 May 2007 (UTC)

It did help as much as the Wikipedia article, which is what gave me this confusion in the first place. :) The bottle was labeled ~16M, and the term "pure molar Hydrochloric Acid" is a direct quote from the professor. 16*3.647=58.352, so perhaps this was a maximum saturation of HCl in H2O?69.29.209.192 07:03, 23 May 2007 (UTC)

[edit] tables and infobox

well done. 141.213.129.41 02:30, 25 Apr 2005 (UTC) the pH is around 2, making it a strong acid. it is found in the stomach, where it catalyses the action of pepsin on proteins, but also kills bacteria.

[edit] As Weapon of Misogynists

Hydrochloric Acid is used in South Asia for domestic use, largely as a toilet cleaner. But another use is by men attacking women in a phenomenon that cuts across the boundaries of India and Pakistan, and while other acids are also used, HCl is the preferred weapon. 99% of attacks are by men on women, though there are some by women on men. This is an issue that needs to be addressed. Is this the correct place?

http://www.womensenews.org/article.cfm/dyn/aid/1908/context/archive http://ww1.mid-day.com/news/city/2005/april/107660.htm

I think there should be a separate article on Misogynist attacks in Asia. Anyone who has Internet access can write such an article. For example, if you are in Wikipedia now and you see the red lettering in Misogynist attacks, you can simply put your mouse pointer on the red lettering and click, and a page will appear where you can start writing such an article. If somebody else starts writing such an article and the link becomes blue (from red), you can still edit the article that was started, giving more information. It would be a good idea to log in under a registered User (member) name when writing the article, but it is not necessary. Also, if you think the article should have a different title, then you can start one with a different title by searching for the alternate title in the margin to the left of this page. If an article with that title is not found, you can start a new one. H Padleckas 17:00, 25 Apr 2005 (UTC)
Have done it as "Misogynist_Acid_attacks", but perhaps it is not yet uploaded? I am getting this message: "If you have created this page in the past few minutes and it has not yet appeared, it may not be visible due to a delay in updating the database. Please wait and check again later before attempting to recreate the page."

The article seems not to exist, unfortunately. However, you should wait for let's say two days before recreating it as I have had such problems too and the article appeared only after about a day. --Eleassar777 16:04, 28 Apr 2005 (UTC)

This article, Misogynist_Acid_attacks, was created, but then had a speedy deletion tag placed on it, then moved from Misogynist_Acid_attacks to Acid attack and slightly expanded. I think you should be able to see the article under Acid attack now. I think the name Misogynist attacks is more suitable than Misogynist_Acid_attacks or Acid attack, because there are similar attacks in those parts of Asia where burning or scalding oil or water are used or women set on fire instead. However, these attacks are not necessarily committed by true misogynists, which are chronic general woman-haters, but men who felt jilted by a certain woman or situation at one time. I don't know what a better name would be. Nevertheless, this topic is important enough to have its own article in Wikipedia.
H Padleckas 04:09, 29 Apr 2005 (UTC)

[edit] Getting off on the wrong foot

I've removed the picture of the shoes.

Yes, it's a picture, and everybody loves pictures.

Yes, I'll even grant you that the shoes are leather.

Of course, hydrochloric acid may very well have been used in their manufacturing.

It's still utterly, completely, and totally devoid of any information whatsoever, and it annoys me. Apt pictures of how HCl is used are acceptable (though I'm not sure the gelatin picture is it) but throwing in leather shoes because HCl is used in leather processing is just silly. You wouldn't mention them in prose, so don't mention them in pictures. Why not add Fonzie's jacket, then? JRM 18:12, 2005 Apr 25 (UTC)

Yay! Support you 100% JRM. I hated the shoes. --jag123 02:10, 26 Apr 2005 (UTC)
Hmm, perhaps a picture of hydrochloric acid being added to leather, or something? -- Natalinasmpf 13:25, 26 Apr 2005 (UTC)

I put the shoes picture in the Wikipedia article Shoe and in Wiktionary under "Shoe" again, so such pictures often can be used somewhere. H Padleckas 18:15, 13 Jun 2005 (UTC)

I support this, too. However, I really would like to see the acid in action. HereToHelp 20:33, 28 September 2005 (UTC)

[edit] Biological section too long

Again the biological section has grown into a too long text, including details that should better be on a dedicated place for it. Could please a biologist take the recommendations from the very useful peer review (link see on top of this discussion page) and reduce that section by half or so? Wim van Dorst 05:10, 2005 May 9 (UTC).

  • Done. Article is now again below the official 30k limit. Please do not re-add the information: this is readily available for the interested reader in the wikilinked subjects in the remaining paragraph. Wim van Dorst 21:28, 28 July 2005 (UTC).

[edit] Referencing

Is it appropriate to include non-open sources (i.e., Akzo Nobel technical papers) in the reference section? I think it is taken as read (or at least hoped) that editors use their personal knowledge when writing articles! Physchim62 21:16, 12 Jun 2005 (UTC)

I think it is appropriate, bearing in mind that there was extensive use made of these technical papers. Also, if something was important enough, it might well be possible to produce these documents- they are not like govt. security secrets. I'm sure our page doesn't contain any proprietary information. Walkerma 23:33, 12 Jun 2005 (UTC)
As indeed a lot of information in this wikipage is based on detailed information from those non-open sources, I intentionally made it as explicit as possible, i.e., put up full reference details. And I can confirm Martin's certainty that, although those documents do contain proprietary information and therefore are non-open, no proprietary info was transferred into the hydrochloric acid wikipage. So Wikipedia is doing the proper thing. And I checked with my Akzo Nobel lawyers about the Akzo Nobel side of doing it like this. Overall, it was done intentionally, and I think it appropriate. Wim van Dorst 20:51, 2005 Jun 13 (UTC).

[edit] Hydrochloric acid in action

I think that a good addition to this article would be a picture of Hydrochloric acid actively eating away at something. I think such a picture is conspicuously absent from the article. However, if has too much shock value, don't post it.--HereToHelp|talk 12:50, 12 November 2005 (UTC)

  • Hydrochloric acid eating away on a piece of metal or so would be booooooring. It isn't really such an active acid as some think: you can actually wash your hands with rust in it (and rinse off quickly, of course). The most atrocious it can do would be to create a bit of rust or so, and ages later dissolve it. If you put very highly concentrated hydrochloric acid on marmer it bubbles a bit (better results with sulphuric acid, school teacher experience here). And a rusty pipe or bubbly beaker wouldn't be an augmentation of the article, in my opinion. If you have a better picture, feel free to propose it (as in adding it). Wim van Dorst 20:34, 12 November 2005 (UTC).
Actually I think there are some possible reactions of HCl, for example with a more active metal that forms coloured ions (Neodymium or Raney nickel come to mind, but I don't have Nd metal). The other possibility is an oxidation reaction that produces chlorine. I'll try to come up with something. It would certainly emphasise the acidic nature of HCl. Walkerma 21:27, 12 November 2005 (UTC)
Wouldn't it over-suggest acidity? It is actually pretty harmless, as acids go. But I'm a sucker for nice pictures, so give it a go. Wim van Dorst 21:42, 12 November 2005 (UTC).
What about HCl with aluminium, not coloured but at least it's something everyday folk are familiar with? I know it reacts nicely after the induction period is over. Walkerma 21:51, 12 November 2005 (UTC) By the way, let's not forget about Image:Hydrochloric acid ammonia.jpg which I think is fun. This is on the ammonium page.
Good idea: this reaction will definitely appeal to a wider audience, especially if we refer it to salmiak. It is a treat in the US too? The picture isn't really nice, though, but will make do, I guess. Wim van Dorst 22:20, 12 November 2005 (UTC).
I commonly use Hydrogen Peroxide to oxidize copper and then add hydrochloric acid to create Copper Chloride... Works quite well, and bubbles a lot. Not to mention you end up with a lot of hydrogen and a low-heat firework colorant :D 67.42.76.182 14:59, 18 October 2006 (UTC)

what would happen if you combined hydrochloric acid to marble chips or little pieces of stone? —Preceding unsigned comment added by 216.8.145.93 (talk) 21:55, 21 October 2007 (UTC)

  • Actually, not much. I tried various concentrated acids for a demonstration in a schoolroom class, and found that only sulfuric acid did anything to marble chips: it makes bubbles (the chemistry is easy). I'm sorry to say that even concentrated hydrochloric acid didn't make a visible impact during the time span of one lecture. Wim van Dorst (Talk) 22:12, 21 October 2007 (UTC).

[edit] Is the ASREC regeneration process text blatant commerce or good tech info?

The text as has recently been added by unnamed IP-numbers about spent acid regeneration process is, in my humble opinion, getting to be blunt commercial advertisements instead of good technical information. Anyone knowledgeable in this field willing to copy-edit that section? Wim van Dorst 22:17, 15 December 2005 (UTC).

[edit] Reaction with sugars when introduced to heat

I heard that when sugars added to HCL, and then heat is applide, the subtstance will combust. Can anyone confirm this? - JedOs 21:53, 20 December 2005 (UTC)

[edit] Bayer product link

Is the recently added link to product info (skimpy imho) of very minor player Bayer (do they produce or only refine?) a worthwhile addition to the article? Wim van Dorst 21:21, 26 January 2006 (UTC).

As our resident industrial HCl expert, I'd trust your opinion. I would take the view that if they are a manufacturer of significance (>1% worldwide or >5% in the particular country) then the link should stay. If they are a major supplier but not an actual manufacturer, I would suggest we need a separate heading for suppliers. If they are neither, and they don't have an important and unique niche (e.g. high purity for electronics or something), let's delete the link. Walkerma 17:03, 27 January 2006 (UTC)

[edit] Possible cleanup needed?

Anyone else see it - there is a lot of information from the info table repeated in the article, are these both required or can we settle for one or the other?

Ryan Jones 00:25, 17 March 2006 (UTC)

This can be a problem, particularly in long articles. I suspect (no evidence to support this though!) that this probably very slowly increases over time, so maybe 1 year after FA we should review this. However I think it's often useful to include the data in the text if they are central to the flow of the article. Can you perhaps list the offending sections of text so we can review them one by one? A bigger problem, IMHO, is the fact that the supplementary data page is largely empty at present (this approach was created after this became FA), we need to fill in the data. Thanks, Walkerma 04:21, 17 March 2006 (UTC)
Ryan Jones: Here are the one I see right off:
* Safety - S-phrases already in info table, repeated?
Thats about the only big one I can find.
Ryan Jones 12:14, 17 March 2006 (UTC)

The listing of the R- and S-phrases is indeed double. It is such a nice table, though, that you'd have to be a butcher to rip it out. The table was created well before the nice templates such R16 were developed by PC, so the table is indeed mostly here for historical reason. Oh, well, if we can't find any other argument than that: sentiment shouldn't hamper progress: out it goes. Wim van Dorst (Talk) 16:07, 19 March 2006 (UTC).

[edit] Notable revertion

Yesterday, the following text was added to the Hydrochloric acid article:

Hydrochloric acid was mentioned on page 7 (third column) of the March, 2006 issue of Chemistry World, a publication of the Royal Society of Chemistry, along with a comment on the speed with which vandalism is removed from chemistry articles in Wikipedia.

It took exactly 72 seconds for this addition to be reverted. QED. This really makes me smile. Wim van Dorst (Talk) 15:35, 1 April 2006 (UTC).

Actually, Wim, I think it took 72 minutes, and our usual vandalism traps missed it because it was (a) reasonable-sounding rather than obscenities or blanking, (b) the edit occurred when Europeans are asleep and (c) the user gave an edit description, something vandals rarely do. But then again, on April Fool's Day we could allow a little humour on the chemistry pages! Walkerma 01:46, 2 April 2006 (UTC)

[edit] Nantionality of jabir ibn hayyan

A quick look in Britannica [1] or Columbia Encyclopedia [2] , and all major Encyclopedia's would tell you that he is an Arab not Iranian. Jidan 14:47, 4 April 2006 (UTC)

There are conflicting sources about his ethnicity, but he's defiantly Iranian-born as per your own sources plus the evidence and discussions on Talk:Geber. --ManiF 14:51, 4 April 2006 (UTC)

[edit] Peerreviewer output

The following suggestions were generated by a semi-automatic javascript program, and may or may not be accurate for the article in question.

  • This article needs footnotes, preferably in the cite.php format recommended by WP:WIAFA. Simply, enclose inline citations, with WP:CITE or WP:CITE/ES information, with <ref>THE FOOTNOTE</ref>. At the bottom of the article, in a section named “References” or “Footnotes”, add <div class="references-small"><references/></div>.
    • To assist you with this, add {{subst:js|User:AndyZ/monobook.js/footnotehelper.js}} to your monobook.js file (mine is located at User:AndyZ/monobook.js) and then bypass your browser's cache by pressing: Mozilla/Safari/Konqueror: hold down Shift while clicking Reload (or press Ctrl-Shift-R), Internet Explorer: press Ctrl-F5, Opera: press F5. In editing mode, click on the "Footnote creater" tab that appears.
  • Please ensure that the article has gone through a thorough copyediting so that the it exemplifies some of Wikipedia's best work. See also User:Tony1/How to satisfy Criterion 2a.

You may wish to browse through User:AndyZ/Suggestions (and the javascript checklist; see the last paragraph in the lead) for further ideas. Thanks, Wim van Dorst (Talk) 20:01, 26 June 2006 (UTC)

[edit] HCl + Al ---->  ?

What are the substances that are produced? --Kalmia 08:12, 25 October 2006 (UTC)

  • 6 HCl + 2 Al → 3 H2 (g) + 2 AlCl3 (aq). If this occurs while unloading hydrochloric acid into a aluminium tank (stupid, stupid, but it happens), and if you're not careful the hydrogen ignites from a spark of the truck: Boom! Wim van Dorst (Talk) 21:49, 27 October 2006 (UTC).
  • Maybe I'll get a picture of the two togethor. --Kalmia 14:24, 5 December 2006 (UTC)

[edit] pKa

This article states the pKa as -8. The Wikipedia article on acid states that the Ka of HCl is is 10^7, therefore the pKa = -7. Fundamentals of Organic Chemistry, an organic chemistry textbook from 1990, says it is -7. I edited this article to agree with the latter two sources.

After having my edit reverted, I looked a little further and it seems that the pKa of HCl and other strong acids is not so clear cut. Atleast according to chembuddy.com the pKa of strong acids is usualy not measured, rather it is calculated based on thermodynamic data. Perhaps depending on the thermodynamic data used, or the model/equation, you can get a different answer. Or maybe this is a rounding issue.-Boonukem

  • Indeed the pKa of strong acids are difficult to determine. It highly depends on numerous other circumstances than just acidity. Therefore most often these values are merely listed as '< 0'. For hydrochloric acid, it also depends highly on the concentration of it. And given a typical concentrated acid at 37%, the pKa then is -8. See also the table in paragraph 2 for physical properties to see how physical properties (notably pH of course) changes with concentration. I propose that in this article the -8 value stands. Wim van Dorst (Talk) 22:42, 7 November 2006 (UTC).

[edit] Is the Acid-to-Water rule valid for Hydrochloric Acid?

water should never be added to the concentrated acid, as this releases enough energy to make the water boil and splatter acid; rather, acid should be added to water

I understood that this rule was for Sulphuric acid. I didn't think it applied to Hydrochloric acid, and I've not noticed a strong heating effect when diluting it. Anyway, even concentrated HCL is already about 65% water.

It goes on to say See references for details, but doesn't link to a specific reference.

Royhills 17:39, 7 April 2007 (UTC)

  • The caution isn't wrong per se, but it is indeed too strict. As written, it applies, as you expected, to sulfuric instead of hydrochloric acid. But don't think that the really concentrated hydrochloric acid (>36 up to 40%) might not be dangerous: always do dilution by adding the acid to water, which ever acid, even acetic acid: that is what safe chemistry is about.
  • Nonetheless, I toned down the paragraph to give more appropriate information. This was a late addition that I had missed. Thanks for pointing out this Opportunity for Improvement. Wim van Dorst (Talk) 21:55, 7 April 2007 (UTC)

[edit] Muriatic Acid

Doesn't Muriatic Acid contain Zinc Chloride? I thought it did when used for cleaning surfaces to be soldered. Anybody?

  • No, muriatic acid (hydrochloric acid) is a pure chemical compound, which does not contain impurities. For soldering, btw, I seem to recall that sulfuric acid is being used instead of hydrochloric acid. And from the welding material it may pick up some metal, converting it to zinc sulfate (not chloride of course). Was this what you're thinking of? Wim van Dorst (Talk) 19:38, 1 June 2007 (UTC).

[edit] References?

For a featured article, this article has a suprising lack of references. This needs to be addressed for the article to keep it's FA status. --203.30.68.49 04:48, 17 September 2007 (UTC)

don't whine or threat: this article had featured status way before most current editors even started using wikipedia! Do something positive and add useful references. Wim van Dorst (Talk) 22:46, 19 October 2007 (UTC).

[edit] Density?

What's the density of 1.0 M hydrochloric acid? --71.142.86.100 03:25, 6 October 2007 (UTC)

About 1.02. Read the table of physical properties. A 1M solution is very dilute. Wim van Dorst (Talk) 22:55, 19 October 2007 (UTC).

[edit] chembox vs new chembox

Today, I have reverted the introduction of the new chembox (by Rifleman), mostly that edit removed a lot of significant information. That the Hydrochloric acid article has been the original of the chembox in the WP:Chem is just n history trivia that should be remembered, but may not be blocking a future introduction of a complete new chembox. Wim van Dorst (Talk) 20:48, 17 October 2007 (UTC).

I've checked manually and I think it's been fixed. Edgar's also helped fix some of the tables the script attacked. Do take a look? Sorry for the trouble earlier. --Rifleman 82 13:59, 18 October 2007 (UTC)
Yep, this looks like a good one. I won't revert this anymore, although being a historic kind of guy I'm sorry to see the good old-fashioned table chembox go, even here in the hydrochloric acid chembox birthplace article. I did re-introduce the major producer information and other external links: these have been IIRC subject of high debates, and IMHO fortunately the decision for 'major producer links' was keep. Thanks for the good work. Wim van Dorst (Talk) 22:42, 19 October 2007 (UTC).