Talk:Hydrofluoric acid

In the environment?

Certain industries emit large amounts of HF. When HF enters the environment and gets disolved, what happens to the hydrofluoric acid? Will the F- just bind to calcium in a stream? 206.170.183.60 16:14, 18 June 2007 (UTC)

Could someone explain why it is so corrosive?

I think we should add a section why HF, despite having such a low dissociation constant, is so corrosive. If the hydronium ions and fluoride ions are all latched together, how come it can react and dissolve all metals except iridium? (according to the strong acid page)
Kr5t 05:46, 6 March 2007 (UTC) Sorry but there are many other metals which HF will not dissolve. I hope people do not take statements from the talk page serously! —Preceding unsigned comment added by 199.64.0.252 (talk) 09:16, 24 May 2008 (UTC)
I think Hydroflouric acid is so reactive despite its dissociation constant is primarily because of Flourine's extreme electronegativity.
~Xdorsih 23:02, 11 July 2009
Some people think acid can not melt glass

Fluorspar

This page erroneously describes "feldspar" as calcium flouride. The correct word is "fluorspar." "Feldspar" refers specifically to silicates of aluminum.

Acid Constants

It'd be nice to have some data on acid constants in all of the pages on acids, really. But I'm afraid I don't have that data.

• This data is coming, at least to those acids covered by WikiProject Chemicals (which includes HF). From memory, the pK_a for HF is about 5. Physchim62 20:57, 29 May 2005 (UTC)

My text book has the pKa at 3.14. Why are there these discrepancies?

hydroflouric acid

Should hydroflouric acid be a misspelling rediret - it's quite common on Google (185 000) and I'm here because I wikified it on Erich Bagge and had to change the spelling that had been used there. Richard Taylor 13:30, 18 August 2005 (UTC)

Done. --Delirium 06:13, August 30, 2005 (UTC)

Potato Chips

There are also food applications for Hydrofluoric acid, including as a potato chip flavouring where it is useful as it can give the acidic flavor required in salt and vinegar potato chips without requiring a volume of liquid which would make the crisps soggy. Hydrofluoric acid is not used for this purpose in all of today's potato chips.

eating hydrofluoric acid?! is this for real?

No, vandalism. Sodium acetate is the compound most usually used for this effect, althouth there are others. Physchim62 (talk) 13:28, 6 April 2006 (UTC)

Hydrofluoric acid (data page)

Please see Talk:Hydrofluoric acid (data page)

Dear readers, I am here to say that what you had just read about hydrofluoric acid is a lie. My fellow friends edited the whole information on the subject on hydrofluoric acid.

I repeat don't believe the info that you just read on hydrofluoric acid.

Correct properties

The page fairly states the properties of hydrofluoric acid as an encyclopedia entry.

Socksysquirrel 00:10, 11 April 2007 (UTC)

Hydrofluoric acid (Reaction)

I am a university student from Malaysia, doing a research on how will hydrofluoric acid react with hydrogen peroxide? What will be the product? Is it dangerous? Thank you!

Nasty Stuff

People, it is best to keep clear of this acid. it is insane. Once saw a lab tech get some on his hand and he was screaming for it to be cut off because it hurt so much. they had to remove a chunk of his hand just to get the hydrofluric acid off. Its best left on the shelf guys.

Just be careful. Use it in small quantities in negative-pressure apparati.

I'd say if you don't have a REASON to be using it you shouldn't be. Like uranium. —The preceding unsigned comment was added by 74.104.1.193 (talk) 04:14, 11 December 2006 (UTC).

The more I learn about HF, the more boggled I am that when I mentored kids in high school (under the guidance of the chemistry teacher!) we etched glass every year. She did warn us all about the dangers of HF (so I assume it was in the etching paste), but given that there were a few craft knife injuries every year, it's just lucky there weren't any problems with the etching paste. -Mel —The preceding unsigned comment was added by 67.135.131.194 (talk) 01:54, 18 April 2007 (UTC).

I used HF for many years in semiconductor facilities. You follow the usual precautions: use a fume hood, wear eye protection and gloves, and proceed carefully. It was not unusual to get a drop or two on the skin; you simply wash it off immediately. One of the risks is if your glove has a hole in it. HF does not burn immediately like sulfuric, nitric, or hydrochloric acid does, so the damage is done before you know it. Stop and remove your glove if you have any suspicion! Some of the older, more careless techs had undercut and even missing fingernails from handling HF without protection. I remember a war story about a guy who spent the night with his hand in a bucket of water trying to relieve the pain. That link about how people are using HF in car washes describes some insane procedures. I've added a paragraph about cardiac risk since it's generally unappreciated that a rather small spill (typically to the legs) can cause death due to cardiac arrythmia. Leg and trunk exposure is a particular problem since some people don't want to disrobe immediately with other people around. One time I was reading the label on a gallon bottle of glacial acetic acid when the bottom fell out (it must have been cracked) and the whole gallon went on my crotch and legs. I stripped off real fast, including underwear, rinsed thoroughly, and no lasting damage occurred. Modesty be damned. A friend had a similar experience with a bottle of fuming nitric acid and watched as his jeans front peeled off and dropped to the ground, taking most of the acid with them. He had some burns, but also rinsed right away. The problem with HF is it's silent but deadly. At least, the poly bottles don't fall apart.--Kbk (talk) 19:25, 9 December 2007 (UTC)

The MSDS explain the hazards associated with HF more convincingly than any testamonials and the MSDS is a verifiable source of information, which is an expectation of Wikipedia, whereas your (or my) encounters are what is called hearsay (sounds insulting but not intended that way). Several fluoride are similarly aggressive. Wikipedia also discourages editors from offering advice, hard as that can be for someone like you or me who has had experience with such nasty stuff as HF and many related compounds.--Smokefoot (talk) 19:43, 9 December 2007 (UTC)

HF Acid Attacking Bone matter

The danger of HF attacking bone calcium and the is a bit over stated: "Exposure to hydrofluoric acid may not be initially painful, and symptoms may not occur until several hours later, when the acid begins to react with calcium in the bones." Wrong. Even with delayed effect the throbbing pain is caused by interference with nerve conduction. You do not have pain receptors in your bones. Death due to hypocalcaemia is more of a concern than necrosis of bone tissue. Exposure to the lungs may lead to death well before any you have to worry about your bones.

"Under most circumstances, hydrofluoric acid exposure results in severe or even lethal damage to the heart, liver, kidneys, and nerves." I have had HF burns, and I know two people hospitalized with serious HF burns from anhydrous HF exposure. They are alive and well and so are their heart, liver, kidneys, and nerves. Immediate medical attention is the key factor in treating hypocalcaemia and tissue necrosis.

What is not over stated: this is nasty stuff. Don't use it unless you know what to do and have access to the appropriate first aid treatments. You need to have a very good plan for working with HF.

• I agree, I will try to have a look at the safety section and keep it to the correct tone. The real risk, as you point out, is immobilisation of serum calcium not the attack of bone tissue: this is why the recommended fist aid is calcium gluconate gel, to flood the affected area with a relatively lipid soluble source of calcium ions. Physchim62 (talk) 08:38, 7 June 2006 (UTC)

SiO2 is not "glass"

the sentance "Hydrofluoric acid is notoriously known to dissolve glass (SiO2):" is grossly misleading at best. silica does not simply = glass!

Actually this statement is true, HF is used to etch glass. My A.P. chem teacher has a piece of glass that he etched his name into with HF. You must remeber that while glass is not pure SiO₂, it is the main constitute. Thus if you dissolve the SiO₂ you are left with compounds that seem to have little or no problem dissolving in HF, effectivly dissolving the "glass." Kyanite 01:37, 26 September 2006 (UTC) Yes, quartz glass is pure SiO2 and is used widely in semiconductor manufacturing. Other glasses such as float, optical, crystal etc. will contain other components, but almost all will have varying amounts of SiO2.

SiO₂ is used as an abbreviation for glass since it's the only chemical component that's especially important. Artificial glasses have additives ("flux") to reduce melting point and reduce viscosity (Na-B compounds are common), but the chemistry of the glass, especially its reactivity with HF, is dominated by SiO₂. Natural glasses are filled with all the things that are present in any rock. Using SiO₂ as an approximation for glass will accounts for the bulk of the system, especially when the topic of interest is "what HF does". The statement should be retained, since the primary importance of HF is to break the Si-O bond, which other acids can't do (only F is appropriately electronegative). This is why HF is used so ubiquitous in geochemistry. Blueschist 18:49, 9 February 2007 (UTC)

It also dissolves boron oxides in borosilicate glasses due to the formation of HBF₄.

Socksysquirrel 01:43, 8 April 2007 (UTC)

Safe % Concentration?

Does anyone know at what % concentrations HF becomes reasonably safe to handle? 1%? 0.5%?

It is classified as Harmful (Xn) in the European Union (under Directive 67/548/EEC as amended) down to 0.1% by mass. Physchim62 (talk) 14:54, 25 October 2006 (UTC)

Dissolve plaster?

Will this dissolve plaster that is skimmed over a brick wall? If so, where can this be purchased. Hydrochloric acid doesn't seem to do much of anything. --Kalmia 08:00, 25 October 2006 (UTC)

I'm sure it would dissolve plaster, but it will also attack the brick underneath. Further, it would be astonishingly dangerous to use in large volumes over large surfaces. The personal protective equipment that you use – even stuff resistant to hydrochloric acid – is apt to be a tender snack for HF. You might try asking at the Reference Desk for suggestions on other ways to remove the plaster, though. TenOfAllTrades(talk) 14:23, 25 October 2006 (UTC)

HF is not actually very good for dissolving plaster (mostly calcium sulfate), as calcium fluoride is pretty insoluble in water. It is also, of course, ludicrously dangerous! Hydrochloric acid is what is usually used: the commercial stuff in France is 22% and works pretty well (HCl has its own safety problems, but less than HF). Physchim62 (talk) 14:48, 25 October 2006 (UTC)

Using HF to dissolve plaster is like using an eraser made of anthrax to erase a mark on the wall. That is to say, a bad idea. Kr5t 05:42, 6 March 2007 (UTC)

I still can't believe that "washing the car with HF" citation in the article. The reference reads more like some kind of complex April Fool's joke, though one printed in January. Maybe the concentrations are at borderline homeopathic levels, but the notion of washing a car with the help of HF strikes me as unable to rise above the merely stupid... mdf 18:13, 23 March 2007 (UTC)

It does appear to be true, if controversial, and it's not at exceptionally low concentrations. It's used in dry cleaning too. Glad I don't have a car... Vashti 04:55, 5 August 2007 (UTC)

The car washing application doesn't seem any harder to believe than selling HF in squeeze bottles for cleaning toilets and sinks. Do a search for MSDS containing HF, you'll be amazed where all it turns up. Jmputnam 16:47, 6 August 2007 (UTC)

Records of undocumented incidents

"records indicating the occurrence of such incidents are not well documented"

I'm intrigued. How does anybody know? -- Ianiceboy 08:12, 14 February 2007 (UTC)

Acidity

I have changed this section to more fairly reflective the properties of this material. It is easy to mix up the corrosive properties of a substance with it's properties as an acid or base.

For example, ammonium bifluoride NH₄HF₂ is only weakly acidic but it is commonly used in glass etching reagents. Socksysquirrel 00:46, 8 April 2007 (UTC)

Nice edits. Why not include something about fluoroboric acid - it is probably manufactured from borax and HF. BTW, Ammonium hydrogen fluoride could use your touch.--Smokefoot 01:54, 8 April 2007 (UTC)

Aerosol concentration limits of HF in humans

The article states that "The highest concentration of HF in air that can be tolerated by a human for 1 minute is 100 mg/m3. This causes a definite sensation of pain on the skin, a definite sour taste, and some degree of eye and respiratory irritation. If the air contains 50 mg/m3, the sour taste is apparent and there is irritation of the eyes and nose, but no pain is sensed on the skin. The concentration of 26 mg/m3 can be tolerated for several minutes, but the sour taste becomes evident after a short time, and there is mild pain in the nose and eyes." While I'm disturbed to learn this, and not sure I want to know how they found this out, this kind of data does need a citation. I'm adding the appropriate tags. -Interested2 02:56, 19 July 2007 (UTC)

How is hydrofluoric acid safely stored?

Somewhere in the article, a description of how hydrofluoric acid is safely stored ought to be included. Obviously, as it etches glass, it isn't safe in a glass bottle. —Preceding unsigned comment added by Pgranzeau (talk • contribs) 20:07, 14 October 2007 (UTC)

It's mentioned right up front. "Because of its high reactivity toward glass, hydrofluoric acid is typically stored in polyethylene or Teflon containers." -- Cyrius|✎ 02:41, 30 October 2007 (UTC)

No. I never get a Teflon Container for it. It's just PP (i'm not sure, but I think HF even reacts with Teflon) --87.162.165.47 (talk) 11:13, 25 December 2011 (UTC)

Wikipedia is not a manual or an advice column: the safety info is in the MSDS

We all want to give advice, it feels good, and with dangerous chemicals like HF, the urge is especially strong, but the necessary content is in the MSDS, which presents the pertinent information more authoritatively and more appropriately than any us could hope for. So the problem is solved, and the articles can focus on information related to the topic, not advice:

From Wikipedia:What Wikipedia is not: "Wikipedia is not a manual, guidebook, or textbook ... Wikipedia is an encyclopedic reference, not an instruction manual, guidebook or textbook.... a Wikipedia article should not read like a how-to style manual of instructions, advice (legal, medical, or otherwise) or suggestions..."

--Smokefoot (talk) 18:23, 3 January 2008 (UTC)

How do you square that with what might be considered "advice" in carbon monoxide, carbon monoxide poisoning, and many of the links in poison and antidote? It doesn't seem to me that there is a consensus regarding what should and shouldn't be in the safety sections of these articles. --Kkmurray (talk) 20:17, 24 January 2008 (UTC)

Well, I can appreciate the effort to keep WP from being a how to. Just for myself, that's why I read the talk pages, to get more casual info, stories or insights that aren't in the main articles. Maybe it's not kosher writing, what have you, but I find the talk pages a very valuable way of getting more "intimate" info on topics. Just thought I'd say that - there's a place for rigid rules - that place is in the main article, IMO. Of course, all spam should be burned. Jjdon (talk) 22:33, 11 April 2012 (UTC)

In Popular Culture

should this section be here? i can't see how it's relevant or appropriate for the article, so if no one has any objections, i'm going to remove it. Coffee joe (talk) 10:50, 26 October 2008 (UTC)

look at the movie 'saw 6'. You can see the effects of HF on human body in the final scene. aergul977@hotmail.com —Preceding unsigned comment added by 88.247.150.223 (talk) 17:23, 27 December 2009 (UTC)

Appearance

What does it look like? When in dilute solution? When at 100%? Just a short description would be good. ie. "Clear blue liquid in solution, viscous pink liquid at 100%" for example. I have no idea what it looks like. Thanks, Tim. —Preceding unsigned comment added by 210.23.136.200 (talk) 10:21, 28 April 2009 (UTC)

The picture on the right shows a clear liquid, and the infobox under the picture says Appearance - Colorless solution. The next line refers to a 48% solution, which I think is the saturation concentration at 25oC. Pure HF is called hydrogen fluoride (as opposed to hydrofluoric acid which is aqueous) and has a boiling point of 19oC so it is a gas at 25oC. Dirac66 (talk) 13:58, 28 April 2009 (UTC)

Criminal Applications

In popular culture, there are references to Hydrofluoric acid being used to being used to dispose of murder victims. I'm not interested in getting back the material Coffee Joe deleted (I hate the tendency for articles to turn into collections of popular trivia), but something on the subject written by somebody with understanding of chemistry or criminalistics would add to the article. Isaac R (talk) 16:21, 25 June 2009 (UTC)

Hydrofluoric acid was used in SAW 6 in the last trap of the game. The victim was injected HFA directly into his body and it dissolved his internal organs. Andy5421 (talk) 16:06, 27 November 2009 (UTC)

Trade names - Prozac and Teflon

At 04:18, 20 July 2009, Alvis replaced the trade names Prozac and Teflon by the chemical names Fluoxetine and Polytetrafluoroethylene, with the edit summary "Wiki prefers NOT using trade names when possible". I would like to ask if this policy is written in a style guide somewhere, such as a page with a name WP:something. My own opinion is that these very familiar trade names would make the article more accessible to readers who may not know the correct chemical names and not realize that we are talking about Prozac and Teflon. We could put both names with the trade name in parentheses: "Fluoxetine (Prozac)" and "Polytetrafluoroethylene (Teflon)". Dirac66 (talk) 00:44, 22 July 2009 (UTC)

Yes. Alvis is wrong. Most of the drug articles (done under the generic name) also include the trade names (which may be many). So I agree you should put them back as you propose above. SBHarris 01:51, 22 July 2009 (UTC)

There's a whole Manual of Style page about trademarks, I guess the consensus is that we can use them quite freely! We even have a featured article whose title is a trademark (Raney nickel). Physchim62 (talk) 09:35, 22 July 2009 (UTC)

Flussäure

Was “Flussäure” the old Swiss German term for “hydrofluoric acid”? --88.78.10.61 (talk) 22:48, 12 November 2009 (UTC)

Looks like it is a German name for this acid, check out [1]. --Smokefoot (talk) 00:12, 13 November 2009 (UTC)

Danger signage

I removed two danger signs from the safety section of this article. Yes, HF is dangerous, but so are many other chemical compounds. In Wikipedia Chemistry, we have not (to my knowledge) applied such signs, deferring to the signage within the "ChemBox" and the information within the MSDS, etc. This approach is codified in Wikipedia:Manual of Style (chemistry). Examples: sodium cyanide or strychnine.--Smokefoot (talk) 03:06, 8 February 2010 (UTC)

Carried Away

"although dont [sic] get too carried away with trying to stick to the 2.5% recommended, too much is better than not enough in this case." There *has* to be a better way of saying this. —Preceding unsigned comment added by 65.94.123.201 (talk) 12:07, 12 September 2010 (UTC)

picture

if someone is bored can you change it to H3O+ F-, similar to hydrochloric

It is a weak acid which does not give away the hydrogen readily, so H-F is the better image.--Stone (talk) 22:00, 25 February 2011 (UTC)

Many answers and links here

http://safety.dri.edu/Hazards/HydrofluoricAcidGuidelines.pdf —Preceding unsigned comment added by 75.4.28.190 (talk) 21:43, 25 February 2011 (UTC)

"In popular culture" addition?

It was used in the season 4 premiere of Breaking Bad (AMC show) to dissolve a body. It would be interesting to discuss if this is possible and mention other TV uses. My interest is because I am a graduate biology student and many chemistry info on the show has been accurate so far. Sometimes the media/hollywood is accurate but usually it is easily dispelled myths (like the gunfights and getting thrown back by a bullet). — Preceding unsigned comment added by 24.239.233.11 (talk) 18:13, 22 July 2011 (UTC)

It was also used in Season 1, that's why Jesse responds 'Trust us'. --201.252.211.41 (talk) 00:27, 14 August 2012 (UTC)

Safe Handling and use

I have reverted this re-addition of a large section on safety per several concerns

• Mostly unreferenced and reads a bit like a copy/paste from a manual; one ref is deadlink.
• Entirely based on Australian regulations
• Overly long for this page
• Contains some (easily fixable) problems with capitalization, spacing, formatting, etc.

This addition needs a rewrite and might suit better in a separate article (e.g. on Australian regulations in handling chemicals). Materialscientist (talk) 04:40, 16 November 2011 (UTC)

Reason for changing definite to indefinite article

The article previously described hydrofluoric acid as "the" precursor to "numerous pharmaceuticals such as fluoxetine (Prozac) and diverse materials such as PTFE". I changed "the" to "a" since this implies that you can make fluoxetine, or PTFE for that matter, using nothing but hydrofluoric acid, which is distinctly inaccurate. There are chemical reactions which have one reactant and one product; this is generally not the case for complex pharmaceuticals. A. J. Luxton (talk) 01:02, 14 June 2012 (UTC)