Wikipedia:Peer review/Hydrochloric acid

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Contents 1 Hydrochloric acid 1.1 Textual improvement discussion 1.2 Discussion about images for the article 1.3 Scope of the article discussion: hydrochloric acid and hydrogen chloride 1.4 Chemistry section is good idea for Hydrochloric Acid article 1.5 HF is not weak 1.6 Cool images 1.7 Are we converging towards FAC status yet? 1.8 Different layout 1.9 Hopefully my final comments 1.10 That's it then

[edit] Hydrochloric acid

Note to housecleaners: This entry has been listed for a month, but please consider leaving it for a while longer, as the discussion is quite active! Bishonen | Talk 01:45, 18 Mar 2005 (UTC)

• Yes, please, I second Bishonen recommendation Wim van Dorst 21:54, 2005 Mar 18 (UTC)
• It it time now. I moved it myself. Wim van Dorst 21:16, 2005 Apr 3 (UTC)

[edit] Textual improvement discussion

This article about hydrochloric acid is fairly complete, and covering the important aspects of the chemical. Before nominating it for Featured Article, I start out humbly by asking for a peer review first. Wim van Dorst 17:37, 2005 Feb 18 (UTC)

This article has some interesting information in it, but at the moment it leaves the reader wanting more. Here's my thoughts: I'm curious as to what it was used for when discovered, what Jabir Ibn Hayyam was expecting when he distilled salt and sulphuric, and whether his discovery was generally known in the middle ages, or independently rediscovered. The history section does not reach up to the present day - that would be useful. The 'applications' section could be considerably expanded, perhaps a paragraph on each item listed there. And the 'trivia' section could probably be named something else, and I'm sure there's more interesting facts that could go there. Worldtraveller 17:52, 18 Feb 2005 (UTC)

• Thanks for the recommendations. The History chapter was elaborated on Jabir, better connect the several historical periods, and link to today. Trivia section renamed (good suggestion!), and I'll up the applications a bit. I don't want to overdo that chapter as that is what the referred-to pages are for. Wim van Dorst 21:04, 2005 Feb 18 (UTC)
• Now also the applications section is elaborated Wim van Dorst 21:55, 2005 Feb 18 (UTC)

Good work! I think the article's much improved now. Some more thoughts - maybe the intro could be a bit longer, and summarise more of the information from the rest of the article? The sections about applications are interesting but I still feel a few of them could be expanded more - regeneration of ion exchangers is a little bit confusing at the moment I think. And in other applications bits, maybe one or two chemical equations showing the reactions that are used? Finally, perhaps more could be said about HCl in nature? Presumably it occurs in other digestive systems than ours? What protects our insides from the corrosiveness of the acid? Worldtraveller 22:59, 20 Feb 2005 (UTC)

• I agree the intro needs expanding. It should be full paragraphs and summarize all important facts about the topic. The rest of the article the writing could use improvement, mostly by making the paragraphs flow better. Eliminating one sentence paragraphs would go a long way towards that. Either expand ideas to stand on their own or merge them together. That is a little hard for this type of topic, but perhaps even more important to make it flow as well as possible. 2) The mention of aqua regia and the alchemists enthusiasm now seems way too broad and even incorrect. Can you find some source to clarify that bit? 3) The production section could use expanding. Those processes cover the obvious simple reactions, but what industrial processes are actually used? Where does the chlorine and hydrogen actually come from? Do they really buy the pure gases and mix them? 4) The facts should probably be named something like other characteristics, and expanded if there are any. In any case the sentence about digestive fluids should be fixed. Do digestive fluids and enzymes really only work on the proteins? - Taxman 22:32, Feb 23, 2005 (UTC)

• Very useful comments, Worldtraveller and Taxman. And thanks for your help in the text (yes, that sentence was indeed as I intented it). After Worldtraveller's recommendation, I already improved the intro-text a great deal, and upon re-affirmation, I further elaborated it. Now I'll be working on the next chapters. PS Sorry that I didn't react sooner, but Wikipedia hasn't allowed me to to editing for the last couple of days, due to 'server recovery'? Wim van Dorst 21:21, 2005 Feb 24 (UTC)
• So, that's an improved intro, improved the applications text, including information chemical reactions (good suggestion!). I also did text flow improvements: have a look whether what you think now. 2) I toned down the aqua regia reference, and removed it from the former 'Facts' paragraph. 3) Yes, you're right, and I did add such information. Remaining problem area, as you correctly point out both: the 'Hydrochloric acid in nature' paragraph. Anybody with additional information? I'm not a biologist. If no addition is forthcoming. what about an 'eradicative text improvement'? Wim van Dorst 22:16, 2005 Feb 24 (UTC)

Apologies for a slow response to your work on this. Good work on the article, it's definitely much improved. The history section is an interesting read. I have a few more suggestions:

• The 'in nature' section definitely could do with expansion - if you're not able to research it, then I'd leave it there, I am sure someone with the relevant expertise will see it at some point, it would be a shame to delete it even if it is a stub-section at the moment. If you mark it as a bio-stub section (if that's possible) it might help biologists to find it.
• I still feel that more could be said about the applications. That section is a little dry at the moment, it could do with some more lively prose (if such a thing is possible when discussing chemical reactions).
• In industrial applications, the article says solutions of up to 38% by weight are produced. Why that particular percentage?
• Safety section - have there been any notable industrial accidents involving HCl? Some kind of incident illustrating the possible dangers could really add to this section.
• There are quite a lot of redlinks - some of them look as if an appropriate article might exist but be incorrectly linked to.Worldtraveller 15:34, 1 Mar 2005 (UTC)

• • OK: I did a biosci-stub, which was improved to sect-stub. I hope to even improve that to interest some biologist, and will do more research myself.
  • OK: What red links? ;-). Pfew, that was more work than I anticipated: I had to do some stub articles, but only after extensive searches to alternatives for linking to
  • OK: elaborated the 38% limit: good leading question!
  • DOUBT: applications text. It lists the applications, and with some detail. Should it be elaborated in this hydrochloric acid article? Would not more details be better placed in the applications it references to?
  • TODO: more safety information
  • TODO: perhaps some illustrations? I have some nice pictures in mind, but I'll have to work on getting them in the public domain first.
  • Wim van Dorst 20:44, 2005 Mar 3 (UTC)

Excellent work on the red links! And the explanation of the 38% limit is great as well. The article's looking very good now. Illustrations would definitely be good, hope you can find some appropriately licensed ones.

Thinking about the application section, you're right that subsidiary articles could be appropriate for detailed discussion, but I think just a little bit extra might help here, e.g. how much HCl is used in each of these processes? What companies are involved? Who uses the products?

Congrats again on great work on this article, I've enjoyed learning about HCl from it! Worldtraveller 11:53, 4 Mar 2005 (UTC)

• Additional research made it possible to replace the biology stub text with some serious information. And I again elaborated that applications piece (do I seem reluctant ;-). The safety data is forthcoming, and give me a week or so for pictures Wim van Dorst 21:36, 2005 Mar 4 (UTC)

• Very good work, and this is really improving. 1) After that research you've done and the rest to resolve the other above suggestions, why not cite those sources directly to those facts? You've just researched them so it should be easy. Ideally use the automatic method at Wikipedia:Footnotes. That method is still in a bit of development, but it does work now and if anything is changed in the future, it will get fixed, so have no fear of using it. 2) Should probably just call the 'in nature' section 'in digestion', since that is all it covers. 3) The only picture I can think of is maybe a standard molecular model representation or diagram of the acid effects. Or I guess a picture of strong HCL acting on something. - Taxman 23:37, Mar 8, 2005 (UTC)

[edit] Discussion about images for the article

--- The research that I did for the biological section was mainly on Wikipedia, and all those sources are linked within the section. Many sources that I used for the rest of the article are documents that I retain from my previous job. As business internal documents, I cannot use them as reference. Where possible I referred to external links on website, and several relevant public sources. --- I renamed the 'in nature' to 'in biology', but I don't like that name either. I would like to have some more references to animal digestive stuff. Further recommendations? Renaming is a good recommendation, but into what? --- For a technical product brochure, I had my hands on some superb non-public domain, copyrighted picture material. Unfortunately it isn't combinable with wikipage publication. Now I'll have to find some other pictures. Sofar I put the Corrosive sign up, and a parchment picture of first discoverer Jabir. I had a dab at drawing a HCl molecule, but that did not turn out well enough for the wikipage. Anybody else better at doing this kind of thing (H white ball, r=1, and Cl green ball, r=4)? I'll be looking for a splash picture for the opening paragraph in the direction of one of the applications. Wim van Dorst 20:11, 2005 Mar 11 (UTC)

• • • Okay, people, choose:

Image:Leathershoes.jpg Image:Leatherswimsuit.jpg Image:Gelatindessert.gif Image:Gelatinsorbet.jpg

• The pictures focus on the small applications, (from left to right Leather Shoes, Leather Swimsuit, Gelatin Dessert, and the last Sorbets (with Gelatin). IMHO these are the most funny and appealing. I guess that a PVC building pipe is very boring :-) Wim van Dorst 21:02, 2005 Mar 11 (UTC)

Great set of images! I like the gelatin dessert one the best I think - illustrative, without being too esoteric I reckon.

On the point about references, surely if the company document has a title and named authors, quoting it as a reference would not be a problem? Certainly, it might be the case that no-one else can actually look up the reference, but at least the source is listed, for the record.

I tried making a quick drawing of the molecule, but it didn't look very good. Could be worth putting a note on WP:RP? I'm sure there's dab hands at this kind of thing out there. Worldtraveller 00:07, 12 Mar 2005 (UTC)

I like that one best too, so that settles it: it is up! And I'll add some more elsewhere in the article. Note that I added the HCl schematic drawing (poor as it is) to the hydrogen chloride page, which tickled the next question: scope (see below). PS. Added an (unpublic) reference in the list too. Thanks for re-affirming the need for it. Wim van Dorst 16:57, 2005 Mar 13 (UTC)

These pictures don't have beautiful models or desserts in them, but they may be helpful anyway. Are either of them useful for the page? I kept them small to save bandwidth but can make them bigger if needed. Sorry I couldn't line up the captions. We might need to add a little to the text if the ammonia one is used, by way of explanation- but this is a classic experiment, worth including. I agree that a titration would be nice, but I really don't have time to set that up right now (new baby any day now!). Also a lorry with a one tonne valic of HCl would be nice! Please let me know if there are other simple pix I could do in less than half an hour that might work better. I could do zinc or Al dissolving in HCl or something like that. Meanwhile I will try my hand at editing the chemistry section- I think it's all good stuff but it should be more concise. Walkerma 05:11, 18 Mar 2005 (UTC)

I'm using the HCl-NH3 picture for the article Ammonium, since that article already specifically mentions that reaction forming NH4Cl. I also would like to use the "HCl fumes on pH paper" picture for the Hydrogen chloride article since it effectively shows hydrogen chloride is acidic.
H Padleckas 07:55, 18 Mar 2005 (UTC)

I have put up a couple more pictures here and here, these show a BOTTLE of hydrochloric acid (with the old-style etched glass label)- one without and one with the pH paper in the fumes. Perhaps the bottle looks more effective than the beaker. Walkerma 17:32, 18 Mar 2005 (UTC)

• See "titration with acid" picture below on the right side. This image can be added next to the Chemistry section of the Hydrochloric acid article. H Padleckas 19:41, 18 Mar 2005 (UTC)

Hi H, the buret acid titration is excellent for the chemistry section. So much so that I already put it up. How's that for support. And Hi Martin, I like the first 'here' (03) best. The glass jar is photogenic. Could you make a picture like this, with a dark background, from a lower viewpoint, i.e., more level to the label? Such a thing could perhaps be worthwhile for the opening paragraph. Wim van Dorst 22:24, 2005 Mar 18 (UTC)

Thanks, H, for the titration image. I will get a "straight on" view of an HCl bottle some time soon. By the way, are solutions of HCl above about 38% actually stable, or do they slowly lose HCl into the air down till they reach 37-38%? Walkerma 04:57, 19 Mar 2005 (UTC)

Regarding stability of concentrated HCl, I think it's all a matter of degree. If concentrated HCl is exposed to the air and allowed to evaporate away, of course it eventually will evaporate away, like even pure water would eventually evaporate away. HCl, being the more volatile component, would preferentially evaporate away more quickly, leaving behind a more watery solution. This preferential evaporation would continue until an azeotrope is reached (or at least approached); then both components evaporate away in the same ratio as the liquid, keeping the solution "stable".
H Padleckas 16:01, 19 Mar 2005 (UTC)

As requested, I have taken a picture "straight on" of a bottle of HCl (Hydrochloric_acid_05.jpg, on the right). Can this be used? If not, please feel free to edit the picture, or give me advice on what picture you would like. One problem we have is- let's face it- HCl isn't that photogenic! While I've been away the page has started to look really good, everyone...! Walkerma 23:06, 22 Mar 2005 (UTC)

Hi, Martin, welcome back. I do like your picture, that is for sure! What if we move the yellow Corrosive sign down to the Safety section, and put this in the top op the table? Anybody comments? Wim van Dorst 22:06, 2005 Mar 23 (UTC)

[edit] Scope of the article discussion: hydrochloric acid and hydrogen chloride

Should the hydrogen chloride page be included in the hydrochloric acid page, or should it be kept as a separate page? Wim van Dorst 16:35, 2005 Mar 13 (UTC) (Note that the other way around is certainly wrong! WvD)

While I don't have strong feelings on the matter and defer to your judgement, I'd prefer keeping the articles separate and expanding the hydrogen chloride page with physical data, application and history information, all of which would be quite different from the information in the hydrochloric acid article. As long as each of the two articles links to the other one in the opening paragraph, I don't think readers will have a problem locating the information they are after; if all the information were combined in one article, it might become a bit overwhelming. Cheers, AxelBoldt 21:43, 13 Mar 2005 (UTC)

I have improved hydrogen chloride from a stub to a reasonable article. On a side note: this hydrochloric acid article really needs a cleanup! There are several weasel terms, multiple wikilinks for the same article, and images that do not really have something to do with the topic. I am strongly against Gelatindessert.png at such a prominent place. The format of the data table is outdated. Maybe I will find the time to fix some of these. (Sig added later: Cacycle 22:26, 13 Mar 2005 (UTC))

Hi Cacycle, using strong words, I think it would be nice if you also sign the comment. And as this is the Peer Review request page, your improvement suggestions are appreciated, as is your work on the hydrogen chloride page.

• Please be so kind as to point out where you consider weasel terms to be used, so that the article can be further improved.
• The images are about the applications (read the captions), so that's not too bad.
• It is also interesting to learn that apparently there is a data table format. Perhaps you would be so kind as to point out where the current version is to be found?
• What is wrong with multiple wikilinks for the same article? I presume you mean that in more than one paragraph, some word is linked to the same page? Wim van Dorst 22:13, 2005 Mar 13 (UTC)

Sorry, forgot to sign. I will take care of the points from above tomorrow. Sorry when my comment sounded a bit harsh. The facts are great, but before nominating it for featured article the text needs some polishing and we need more appropriate pictures or illustrations. Cacycle 22:26, 13 Mar 2005 (UTC)

From the Talk page of Hydrochloric acid, I moved the following Questions to here:

• In this formula, R.H + HF → R.F + HCl , where does the Cl atom come from?
• What household products use HCl?

--jag123 22:10, 13 Mar 2005 (UTC)

The fluoridation reaction is a chlorine replacing reaction. Typo in the formula, now corrected. And the household application that comes to mind is builders cleaner, to take care of mortar stains or so? I'm not detailed familiar with it. It is also bottled under the name of muriatic acid (fortunately low concentration) for unnamed household purposes. Please don't let them throw a dollop in the toilet after they cleaned it with bleach (sodium hypochlorite)... Wim van Dorst 22:42, 2005 Mar 13 (UTC)

At least one household toilet bowl cleaning formulation has mainly semi-strong hydrochloric acid in it, Sno-bowl??. H Padleckas 05:57, 31 Mar 2005 (UTC)

The images currently don't have captions; you only get to see the text if you "mouse over". I think it would be good to have the captions visible, and to move the gelatin picture further down to the applications section. As main picture, maybe a photo of a bottle with hydrochloric acid, carrying the common warning label? AxelBoldt 18:31, 14 Mar 2005 (UTC)

• I think some of these pictures can be removed. I read the article and don't really remember how HCl is related to jello. The bottle label is a good suggestion and should definitely be used. Maybe a diagram of the reaction of mustard gas producing HCl or a diagram of parietal cells producing HCl. Not the best, I know, but a tad more relevant than a pic of shoes :) --jag123 18:45, 14 Mar 2005 (UTC)

• • I disagree about removing images, I think the images used brighten up the article, the dessert one particularly. What could be done though, is for their relation to HCl to be made clearer in the text. Another image that could be interesting, if available, might be a photo of an industrial HCl processing plant. Worldtraveller 23:49, 14 Mar 2005 (UTC)

• • • We must have two separate pages for hydrogen chloride and hydrochloric acid, these are both very important commercially and they have different properties. I would argue that hydrochloric acid is in fact hydronium chloride, since there is very little actual undissociated HCl present in a bottle of hydrochloric acid! That means for example that hydrogen chloride is in fact a much stronger acid than hydrochloric acid. BTW, I have taken a few pictures of hydrochloric acid itself, I apologise they are really boring, they don't have any models in fancy shoes in them! I'll upload them ASAP. Walkerma 17:23, 17 Mar 2005 (UTC)

[edit] Chemistry section is good idea for Hydrochloric Acid article

My opinion is that a Chemistry section is needed for this Hydrochloric acid article. I'm writing it now. I will add it when I'm finished. H Padleckas 21:33, 14 Mar 2005 (UTC)

ok, I finished my first crack at the "Chemistry" section in the Hydrochloric acid article. Check it out. I noticed very recent significant improvements in the data table in this article, some of which I wanted to make myself. H Padleckas 01:12, 15 Mar 2005 (UTC)

I'm essentially finished with the "Chemistry" section of this article. In case any reviewers think this Chemistry section is lengthy technical overkill for the average Wikipedia reader, I volunteer that the two sentences starting and ending with

"This is supported by the fact that ...... completely dissociates in water."

are expendable. Deleting them would not likely cause a great loss to the overall understanding of the article. Also, some of the length comes from short explanations I put in trying to make this a once read-through section (to a practical extent) so the average Wikipedia reader would not have to constantly use links for an understanding of some fundamental terms. If I was writing this for professional chemists, some of those explanations would be omitted.

The data table for hydrochloric acid is significantly improved now after the last two or so edits.
I was planning to take some of the information on synthesis and/or production of hydrogen chloride for insertion into the Hydrogen chloride article. As far as I'm concerned, that information can stay in both articles. I plan to put a data table in the Hydrogen chloride article which in many instances contains different data than the Hydrochloric acid article. That project is still in progress. H Padleckas 16:21, 15 Mar 2005 (UTC)

• Hi, H, I fully second your proposal of a Chemistry section. And as you worked it out it sure is an asset to the article. It is rather a big chunk of text, so I would think further editing would ??imho?? in my humble opinion be directed at making it more concise. Perhaps a picture to lighten it up? And is the Wikipedia idea that all text ought to be understandable by everybody? I would like it to make various in-depth sections for experts only. And to all who contributed to the new data table: kudos! Wim van Dorst 21:57, 2005 Mar 15 (UTC)

My idea is that a picture of a titration with a burette and an Erlenmeyer flask might be appropriate or picturesque near the Chemistry section of Hydrochloric acid if you want to "liven up" the "dry" Chemistry section of this article. I found one such diagram in the titration article and an identical diagram in acid-base titration. It is a somewhat tall and thin image. The color inside the Erlemeyer flask shows a newly added droplet turning pink, which would be expected if the titrant was a base, not an acid like HCl. This color effect should be reversed when HCl is the titrant. Should I or somebody try to work on this? There are probably other pics of titrations on the web, but they are likely to be copyrighted, so I did not explore the web. I looked in Wikimedia Commons, but I did not find a titration picture.

• I completed the acid titrant picture and placed it here for your viewing. This image can be added next to the Chemistry section of the Hydrochloric acid article. H Padleckas 19:41, 18 Mar 2005 (UTC)

My lengthy, philosophical, and not particularly relevant answer to Wim van Dorst's question "Is the Wikipedia idea that all text ought to be understandable by everybody?" has been moved from here to my User page as a philosophical statement, so that this lengthy page may be shortened. H Padleckas 19:00, 3 Apr 2005 (UTC)

• • The datatable is now about 37% hydrochloric acid, which is not the major concentration worldwide: that is 30%, which has some different numbers and which I used for putting the data in the datatable in the first place. Should we cater for more than one concentration? If so, how, if not which one to use?
  • In my book the R/S statements for hydrochloric acid are R34-27 and S26-45, no S36. Where did that come from? And where is it to go?

Wim van Dorst 22:10, 2005 Mar 15 (UTC)

S36 is from my Aldrich catalog. Data for more than one concentration seems a bit overkill. Anyway, it would only affect density, melting point, and boiling point. The CAS number is probably for plain HCl. I have chosen 37% because this is the highest possible concentration and is kind of a 'chemical standard'. Cacycle 23:00, 15 Mar 2005 (UTC)

Hi Padleckas, I like the titration picture proposal. Give the huge range of pH indicator and very nice colour changes they can give, this is a nice idea. It is a pity that it emphasizes the laboratory use which for the commercial market is negligible. And also for Cacycle, the 37% is a chemical standard only in the laboratory, and even then it is not THE standard: 36% and 38% are just as common for concentrated hydrochloric acid. And in the industrial 30% is the real big thing, hence my choice for that as the reference material for the table. So if you would insist on only one concentration, I would recommend 30% instead of 37%. But the important conclusion that I drew is not either/or: I think it not overkill but necessary to have more than one concentration. Apart from the properties that you mention, also vapour pressure, pH, and viscosity are highly dependent on the concentration. I therefore propose to add a table with chemical and physical properties for various concentrations: 5% 10% 20% 30% 32% 34% 36% and 38% seem reasonable. Perhaps also a 0% for reference? I'll work on this tomorrow or so. Wim van Dorst 00:17, 2005 Mar 18 (UTC)

If you do a table, one important concentration to put in is that of constant boiling HCl, i.e. what you get if you distil conc. hydrochloric acid. I think it's about 20% from memory- but I'm sure you know, Wim! I hope you approve of my rewrite of the chemistry section, I tried to make it clearer without taking away any real content. Walkerma 06:30, 18 Mar 2005 (UTC)

The table is a good idea, but I would either make a diagram with curves or concentrate on a few important values (10, 20%, 30%, 37%) and put also the molarity in there. The constant boiling one is 20.2%, bp 109 / 110 °C. The maximum seems to be 72% at 20°C. It seems that there is nothing special about the 37% as I always thought. Or is it?

Given the question about which solution is stable (actually only the 0% is :-), and the reference to only one of hydrochloric acid's several eutectica* I really should get my hands on a usable phase diagram. The one I have is copyrighted, but I hope I can draw one myself for the public domain (perhaps based on that same data). I wish there would be a possibility to use copyrighted material, as the one I had made for my commercial brochure is imho very insightful. Work on the table has started (off-line editing first) Wim van Dorst 11:14, 2005 Mar 19 (UTC)

 *eutectic or azeotrope? An azeotrope is a constant-boiling liquid mixture (to vapor at a certain temp.) at a certain % for each component. A eutectic is something similar for solids melting. I have added a sentence at the end of the Chemistry section and in the table on the 20.2% HCl-H₂O azeotrope. The azeotrope should also be stable as far as evaporation is concerned, as well as the individual components when they are separate, of course. Any eutectics of HCl-H₂O would be of less interest for practical purposes and may be omitted for a general information article such as this. H Padleckas 16:01, 19 Mar 2005 (UTC)

There is a table of data on HCl in the it:Acido cloridrico article in the Italian Wikipedia, to which I already added a link to in the English Hydrochloric acid article. The Italian table includes %HCl, g HCl/100 ml water, molarity, and density. There is also a fairly simple equation there correlating a couple of properties. H Padleckas 18:00, 19 Mar 2005 (UTC)

• The reference data for the Italian pages gives quite some remarkable info, e.g., Toxic; All these R and S statements (they not a free choice, you know); rather arkane production method. As my Italian is below-par, I cannot judge the rest of the text, but overall I'd rather not use the data as-is. My table is based on solid references, so that's reliable. I like the molarity/molality info. I'll try to put my hands on reliable data.
• The cristallization information is highly relevant for people who want to store hydrochloric acid in a tank outside. If it freezes over at -10°C, the acid supply to the production plant stops, and something unpleasant could happen to the whole site. So, knowing that there is a deep eutecticum between 20 and 30 wt% is very important. You could leave this out of lab chemical description, but not out of the description of a major industrial chemical description as hydrochloric acid. Wim van Dorst 21:03, 2005 Mar 19 (UTC)

Is the specific heat capacity important for the table? If so we should elaborate on it. Boiling and melting points would be interesting values to add to the table. I also like the orange symbols on the italian article. Cacycle 13:30, 20 Mar 2005 (UTC)

• I added the mp and the bp to the table, but you deleted them again. WHY??? I didn't make a typo. Did you? Wim van Dorst 18:33, 2005 Mar 20 (UTC)

• Oops, that was not intentionally. Strangely, I can't remember any edit conflict page!? Anyway, I have put your changes back in. I will try to make the table smaller. I'll also check if it looks better to move °C into the value cells. Cacycle 21:54, 20 Mar 2005 (UTC)

• Your table work is outstanding: content is very good of course (imHo), but the presentation is giving it the best result. Compliments. Where do you get the information about these parameters that you used? PS. You (probably unintentionally?) undid my reshuffling of the MSDS references. Would you mind clarifying if you did it intentionally, and if not put it back? PPS. Where you the one too to re-insert the categories on the bottom, which I had removed to prevent double listing? Note that I don't mind at all if my changes are undone, just as long as there is a good reason (which I can challenge if I disagree). Wim van Dorst 09:30, 2005 Mar 21 (UTC)

• Which parameters? I have simply calculated the molarity from molecular weight, concentration, and density. I'm not sure what you mean with "reshuffling of the MSDS references", so it was probably unintentionally :-) As for the categories: [[:Category:Chlorides]] doesn't put a page into a category but merely generates a link (simple link, not a category: Category:Chlorides). Cacycle 14:21, 21 Mar 2005 (UTC)

Oh, you are refering to CSS and HTML? You can find some tricks by following the Editing help pages, e.g. in Wikipedia:Picture tutorial. The rest is trial and error using css and html code. Cacycle 14:21, 21 Mar 2005 (UTC)

[edit] HF is not weak

Saying HF is weak is not really accurate. It may not dissociate easily in water, but unlike the others HX, it's the only one that can etch glass. It's only weak in terms of dissociating in water, which doesn't really mean much.

This discussion should really be moved to the article's talk page, where it should have started to begin with. The peer review subpage is not the place to discuss everything but to alert people what needs to be looked at. --jag123 14:52, 20 Mar 2005 (UTC)

You're right in pointing out that the strong/weak acid text needed improvement: I changed it to better indicate which monoprotic acid is what. That HF can etch glass is true, but has nothing to do with its acid strength. I disagree that this discussion should be elsewhere: the directive on top of the Peer Review page clearly states that any comments are to be added to the specific section. You'd better be happy that there is this lively discussion about a page under Peer Review. Wim van Dorst 17:07, 2005 Mar 20 (UTC)

I know etching of glass isn't a gauge of acid strength, but I still think characterizing HF as weak is misleading. The chemistry re: HF is pretty much unique, because of the high electronegativity and especially the entropy / ordering of water molecules around HF (which is really something like FHFHFH..., unlike the other HX). Weak/strong acids is purely a chemistry qualification. HF may not dissociate fully in water, but it'll dissociate if it comes into contact with other elements. People shouldn't assume that HF is weak, like vinegar (which many people do). HCl, on the other hand, is a strong acid, both in the chemistry and "practical" sense. Anyway, I've removed the last sentence, and I don't think it changes the article. On top of it, I had/have a problem with "common halogens". Astatine isn't common partly because it's useless; half-life of longest living isotope is 8 hours.

And yes, I am happy that there is peer reviewing on these types of articles. There needs to be more FA regarding science. --jag123 13:22, 21 Mar 2005 (UTC)

Hi Jag123 (couldn't find your normal name), your final change to the text first took me by surprise, but after all I actually like it: the paragraph is more hydrochloric acid focussed as a result, and therefore I think also better. Good change. Perhaps you can do a little editing to pages such as strong acid and weak acid, where the arguments you bring forward will have a better acceptance. And at the rate of change the hydrochloric acid page is still being improved, it looks like it may never be stable enough for FA status :-). Wim van Dorst 16:43, 2005 Mar 21 (UTC)

I'm glad you like my changes. I'm not trying to convert the world regarding weak/strong acids, but I just didn't think that sentence was important enough to the article to leave it in. I guess I keep thinking this will be eventually an FA and want to keep the average person in mind. Hopefully I don't pass off as being too anal, but this "HF is weak" thing is somewhat of a pet peeve of mine :) --jag123 19:19, 21 Mar 2005 (UTC)

I admit I reinserted the sentence on halogen acids stating HF is weak, then modified it to say that the other 3 are strong acids and HF is an acid that does not fully dissociate. I think this is probably my last shot at it and you guys can keep it, change it, or take it out. H Padleckas 21:18, 21 Mar 2005 (UTC)

I still don't see why this is important to mention, but whatever. --jag123 22:49, 21 Mar 2005 (UTC)

Sorry, Padleckas, but I agree with Jag123 here: the wordiness of the paragraph doesn't add to the article about hydrochloric acid. I recommend that this information be moved to a dedicated page about monoprotic acids. Wim van Dorst 23:17, 2005 Mar 21 (UTC)

I expanded the "Chemical characteristics" section of the Acid article to discuss monoprotic, diprotic, triprotic, etc. acids. H Padleckas 05:57, 31 Mar 2005 (UTC)

[edit] Cool images

Here is a German page with cool images: http://www.seilnacht.com/Chemie/ch_hcl.htm Unfortunately the images are copyrighted and it doesn't look as if we could convince the guy to put some of them under GPL or into PD. BTW, I have uploaded all orange hazard symbols to the Wikimedia Commons. Cacycle 20 Mar 2005

Yes, there are plenty of very nice pictures around, but then nearly always copyrighted. I saw that you uploaded the correct one to the approporiate place already: good idea. I was thinking about doing the same. Wim van Dorst 18:33, 2005 Mar 20 (UTC)

Anyone know what the color of a common indicator that is used with HCl? It's really easy to change the color in titration picture, but I don't know which color is best. --jag123 13:26, 21 Mar 2005 (UTC)

Perhaps the most common indicator used in acid-base titrations is phenolphthalein, which is colorless in acidic solution and magenta in basic, as shown in the above picture. The titration shown here with an acidic titrant, such as HCl, is the reverse of the original picture in titration, in which apparently a basic titrant is used with phenolphthalein. However, many different acid-base indicators can be used in an HCl titration, at least a couple dozen kinds. This variety of indicators covers most of the pH range. These indicators have a variety of different colors at both acidic and basic pH. About a dozen have been listed in the Wikipedia article on indicators.

Also, I didn't see any good reason for removing the sentence on the 4 common halogen acids of the form HX from the Hydrochloric acid article, so I reverted your edit. H Padleckas 19:36, 21 Mar 2005 (UTC)

See end of section "HF is not weak" above. H Padleckas 21:18, 21 Mar 2005 (UTC)

Thansk for your answer. It didn't really click that the analyte was changing from pink to colorless. --jag123 01:11, 22 Mar 2005 (UTC)

[edit] Are we converging towards FAC status yet?

Hi all, since February 12 the hydrochloric acid page has seen on average between five and ten smaller and (mostly) bigger changes on a daily basis. It is my humble opinion that most significant suggestions from the beginning (read up higher here) have either been implemented or else discussed out of the article. Some things have been found to be unachievable within this short timeframe such as eloquent pictures, but worthwhile other things have been added unexpectedly (at least for me) such as the Chemistry and the Chem Phys properties table. Obviously, the page won't ever be finished. Could we then suggest that we close the Peer Review and put the page up for Featured Article Candidate? Or are important things still missing, pictures still forthcoming RSN, battling discussions to be finalized? Wim van Dorst 19:59, 2005 Mar 21 (UTC)

I still have a significant suggestion for a change to make in the HCl acid article. A couple of days ago, a new table with physical properties was added with the first column containing the Conc. (w/w) apparently being the independent variable on which all the other values in the table are based. Of the properties given in the table, Conc. (w/v), Density, Molarity, and Specific Heat depend on temperature and Viscosity and Vapor Pressure depend quite strongly on temperature. I can't find any reference temperature listed in or near the table at which these values are true. There should be a reference temperature given for this data. Such a temperature should be listed wherever the data was originally obtained from. It might be something simple like 25°C or 0°C, but it should be provided for the properties I just mentioned. No reference temperature is applicable to the Boiling and Melting points, but the reference pressure is probably 1 atmosphere (101.325 kPa). You could probably nominate the article for FAC, then look for the reference temperature, but for correctness, it should be added sooner or later.

Also, the first sentence in the Physical properties section refers to the table at right. On my computer screen, this table does not appear to the right of the sentence, but far above it. Of course, you may decide to refer to the table below it instead. H Padleckas 20:48, 21 Mar 2005 (UTC)

• Hi H, this was an easy addition, both already done (it was 20 °C and 1 atm) . I take it you support the move to FAC, then? Wim van Dorst 21:17, 2005 Mar 21 (UTC)

Someday, I plan to take some information directly related to the history, synthesis, and production of hydrogen chloride from Hydrochloric acid and add it to Hydrogen chloride. I might start a new section in Hydrogen chloride article called "History, Synthesis, and Production". This does not mean that this information has to be deleted in the HCl acid article; the information can stay in both articles as far as I'm concerned, although somebody may say that's a duplication of text in 2 articles. Other than this final observation, I think Hydrochloric acid is ready for FAC nomination. H Padleckas 22:35, 21 Mar 2005 (UTC)

I have essentially finished doing the above, i. e. I've taken info from Hydrochloric acid and placed it into Hydrogen chloride. For more details, see the hydrogen chloride article and Talk:Hydrogen chloride. Now you can decide how this info should be distrubuted between the 2 articles. Also see my hopefully final comments on Hydrochloric acid below. H Padleckas 05:57, 31 Mar 2005 (UTC)

Thanks for the support, Padleckas. Nonetheless, your long text in the footnote doesn't add information. I recommend the intentionally short sentence. Wim van Dorst

• Before this goes to FAC, I'd like to clean up the biology section a bit. I think there's a bit more info that can be added here. (Iirc, there's a beetle that uses HCl [or a mixture of acids including HCl] as a defense mechanism.) I want to double check academic journals to see if there's been changes/developments in the HCl synth mechanisms in parietal cells, and if there's no difference, at least find a journal that I can use as reference for what's there. I'd like to find something that can be complemented with a picture, which would ideally replace the shoes (which I think are not really relevant). --jag123 01:07, 22 Mar 2005 (UTC)

• Considering the current pace of changes I would wait with FC nomination until contributions slow down. There are a still a few facts I would like to add (e.g. use to make hydrochlorides) or would like to see improved (e.g. biology section, images, the confusing uses section). Before nomination, when all facts are in place, we should proofread and polish the article in a concerted action (e.g. remove unimportant or redundant facts, words, and sentences, improve sentence-to-sentence flow, make the final layout). Cacycle 09:38, 22 Mar 2005 (UTC)

Indeed I now see the convergence stepping in over the whole article: good housekeeping has been done on biology, references and other sections; final (as if they are ever) text improvements are added; and the good toothcombing work is also being done now by Cacycle and Padleckas (thanks, others invited to participate of course). Overall, the additions are slowing down (or is it just Easter?), so I propose to move to FAC in a week from now. And remember that future additions, elaborations and other improvements remain possible, even as a FA. Wim van Dorst 10:25, 2005 Mar 28 (UTC)

[edit] Different layout

Different layout I've moved the history section above the chemistry section because the tables were one on top of the other on my end (1024x768, IE6). I also think it flows better, since the chemistry, production & application sections follow each other. If this looks worse than before for anyone, revert. --jag123 01:24, 22 Mar 2005 (UTC)

• Good idea to change the sequence. I also had the tables clashing. And the text indeed flows better.
• Why to explicitly add the section for other languages? Isn't that extra: they are already listed in the left Wikipedia-column. Considering that the Categories are also listed at the bottom, I was actually considering to take these extra things out too. Please comment?
• Which Uses do you mean to be unclear: the last paragraph of the Chemistry section or the Applications section?
• As already pointed out, I am no biologist. Any improvement (with images) to the Biology section is worthwhile!
• I won't put it up for FAC yet, with this update rate. But I wondered whether we are converging... Wim van Dorst 20:50, 2005 Mar 22 (UTC)

The idea was to have the names in other languages in the article, the links to the other wikipedias are just a gimmick (some languages (like Latin) where I have found the name do not yet have an article on hydrochloric acid). I have not yet found such a list on the web, but I will try to figure out the names in some missing more important languages. Cacycle 23:18, 22 Mar 2005 (UTC)

Perhaps the names in other languages should be moved to the first paragraph, or given a separate paragraph in the intro section? Regardless, I think it somewhat pointless to include links to other Wikipedias, mainly due to redundancy. →Iñgōlemo← ^talk 23:26, 2005 Mar 22 (UTC)

More upwards it would be too confusing and crowding. I like it there, close to the safety section (it is somehow safety-relevat to know the name of a chemical in other languages) and some other bulleted list. I see no reason not to link the names. Sometimes it just makes sense to have more than one link to another article, especially in tables and lists and if the link words are different. Cacycle 00:39, 23 Mar 2005 (UTC)

I've been mostly peripheral to this review, but I wanted to say that the article does look very nice to me, and pretty close to being ready. My only suggestion might be to try making the other languages section more compact (perhaps a table, with one column per group of languages?)- currently that section fills one whole screen on my PC. This is a minor point, though and I think overall it looks pretty finished. Great job, everyone! Walkerma 06:12, 1 Apr 2005 (UTC)

[edit] Hopefully my final comments

I'm sorry it took me (H Padleckas) several days to finish writing these explanatory comments up. My hopefully final review of the Hydrochloric acid article results in these comments:

I've decided to strike out those comments for which satifactory (in my opinion, of course) changes in the article have already been made, like this: comment.
H Padleckas 17:38, 1 Apr 2005 (UTC)

• Is the phrase "sizing nowadays" in the introductory section good style?

It took me three read-throughs to catch the style error: you're eagle-eyed, Padleckas. Obviously, it is reworded now.Wim van Dorst 18:02, 2005 Apr 1 (UTC)

• The last sentence in the introductory section is clumsy ; i. e. gelatin production is not a food ingredient; gelatin is a food ingredient. Reword how you want to.

Yes, it certainly was clumsily worded. Wim van Dorst 18:02, 2005 Apr 1 (UTC)

• I changed the neutralizing reaction in the section "pH control and neutralization" to:

OH^- + HCl → H₂O + Cl^-

to show that it's HCl acid that does the neutralizing and that after neutralizing Cl^- is present. The previous reaction was just the reverse of the water ionization reaction.

• There is practically nothing about "metal surface treatment" in the link to Metallurgy in the "Pickling of steel" section. I suggest removing the link.

Yes, indeed, there is very little information about the topic. I searched some more and did find some better references to the detailed techniques, although not to the generic term. I reworded the paragraph, removing the offending link, and inserted a few better ones. Wim van Dorst 18:23, 2005 Apr 1 (UTC)

• In the "Pickling of steel" section, the previous link to scale gave a disambiguation page with no applicable article written. The chem. reaction shows Fe₂O₃ + Fe reacting with HCl. According to the Wikipedia, rust is Fe₂O₃. Fe is definitely not scale but metal. When I think of "scale", I think of deposits on surfaces (such as inner surfaces of pipes), typically coming from hard water and possibly soaps/detergents, which usually consist of calcium/magnesium carbonates, phosphates, or soap scum. Hydrochloric acid can help dissolve carbonates, the most likely form of scale. Therefore, I changed "scale" to "rust or scale".

Actually, as I understood it from extruders, whereas it chemically is rust, it is also named 'scale'. Your text change was therefore very good. Wim van Dorst 21:06, 2005 Apr 1 (UTC)

• MDI and TDI for polyurethane are not defined/explained in this article, although they are mentioned twice. The link to polyurethane doesn't explain them either. MDI is methylene diphenyl 4,4'-diisocyanate and TDI is toluene diisocyanate. They are both isocyanate monomers for the production of polyurethane polymers. I made links for TDI and MDI redirected to Isocyanate where I am currently in the process of writing about these compounds.

Excellent!!! I tried to find MDI/TDI information at the beginning of this editing spell, but didn't find any. Your change is spot-on! Wim van Dorst 21:06, 2005 Apr 1 (UTC)

• The Hydrochloric acid article has become quite long (30 kilobytes) and could stand to be somewhat shortened. This can be done by taking out unnecessary detail in the "Hydrochloric acid and living organisms" section and transferring it to shorter articles. The discussion on parietal cells in "Digestion" can be shortened by moving the details to parietal cells, a much shorter article. The discussion on osteoclasts in "Bone resorption" can be shortened by moving the details to osteoclasts, which is presently just a stub. The same applies to the phosgene discussion in "Chemical weapons". Also, most Wikipedia articles simply include the links to corresponding articles in other languages on the left side margin, instead of at the end of the article proper like here. The article can be shortened by deleting the foreign language links section and using the side links only.

• I always thought using the term HCl in regards to biology, especially digestion and bone resorption was somewhat innacurate, compared to the industrial uses. It's only HCl because Cl- is a common negative ion that gets included to offset the positive charges. Without getting into lengthy discussions on evolution, the fact that it's HCl is somewhat arbitrary. I won't touch anything until Wim gives his input, but I agree with the above. --jag123 20:48, 1 Apr 2005 (UTC)
  • Actually the biology section is more written by Cacycle and others. I do support Padleckas' recommendations, though, for reducing that section. Anyone knowledgeable in biology to do it? And notably I support the recommendation that we delete the language section: I liked quite a bit seeking for those outrageous languages, and re-organizing the section itself, but it is a bit of an odd one out. Wim van Dorst 21:56, 2005 Apr 1 (UTC)
    • I've went ahead and shifted the information to other appropriate articles, and written an extremely short summary of what used to be here. I've left the chem weapons section intact because it looks like it can't easily be copied into their respective articles, and I don't want to remove info without copying it elsewhere first. I also went ahead and removed the language pages, and added greek in the interwiki language section. --jag123 22:42, 1 Apr 2005 (UTC)

• In the discussion about chlorine and phosgene in the "Chemical weapons" section, "carbon monoxide" was previously changed to "carbon dioxide" for consistency with the phosgene article. In that article, CO and Cl₂ are used to produce phosgene, but the reaction with water gives CO₂ and 2 HCl. This is also consistent with the "Chemical Warfare_v2.pdf" webpage of this external reference |Chemical warfare, and my understanding of organic chemistry. The reaction with chlorine gas also cannot produce any carbon oxides, and the mention of chlorine was also suspect in this paragraph. So I technically agree with the edit made by Cacycle on this topic. However, my suggestion is to shorten this article by shortening the phosgene discussion to be similar to the mention I originally made. Also, a mustard gas molecule has only 2 Cl atoms and cannot give 3 HCl, as the first external reference in the mustard gas, [1], states. I believe that reference is incorrect about reacting with water to give 3 HCl molecules. I made a correction to fix this in Hydrochloric acid.
• Also, one may want to see my remarks in Talk:Hydrogen chloride to coordinate any information common to both articles, if you haven't seen them already. As time permits, I plan to add a little more info not mentioned in Hydrochloric acid to the Hydrogen chloride article.
  H Padleckas 05:57, 31 Mar 2005 (UTC)

[edit] That's it then

Ok, guys (I believe no female participation sofar? Women invited, though): Changes have been structural to the discussion, there are no open issues at present, the article has been updated, enlarged, comprised, reduced, enhanced, elaborated, augmented, illustrated, completed, and improved. Thanks to you all! I'll now move it to the FAC page, to see what others think of it. Wim van Dorst 20:54, 2005 Apr 3 (UTC)

yay!!!  :-)   I wonder how you knew I'm male. H Padleckas 21:47, 3 Apr 2005 (UTC)

High five!! It's now a highly rated FEATURE ARTICLE! Congratulations to Wim van Dorst and all other contributors and reviewers. H Padleckas 08:35, 8 Apr 2005 (UTC)