Talk:Sodium hydroxide

Safety information

The line "skin should be washed thoroughly with water following contact with this substance" should probably have "and then flushed with vinegar." appended to it, but I couldn't think of a good way to put that in words and I didn't have a citation either, unless Fight Club or the Roebic web page have something to day. That is, however, the directions on the back of this here bottle of drain cleaner and it claims to be pure sodium hydroxide. —Preceding unsigned comment added by 24.125.43.51 (talk) 19:37, 21 July 2008 (UTC)

Reference to Edward Gorey (R.I.P.) in somewhere?

Well, I basically summed everything up in the title. Should there be mention of the Ghashlycrumb Tinies in which one child "Takes lye by mistake"? --Arkracer 21:46, 17 November 2006 (UTC)

Use of Sodium Hydroxide in Food and Consumer Goods

Could someone please give some detail about how sodium hydroxide is used in cleaning the flesh off of bones? --Cyberman 22:16, 10 July 2005 (UTC)

If lye is poisonous, how do they contrive to make food with it? - Montréalais 23:30, 1 Nov 2004 (UTC)

Topol whitening toothpaste contains sodium hydroxide. I know toothpastes usually have a myrid of chemicals, but is Sodium Hydroxide useful in teeth whitening? [Ingredient Reference]

Both this page and the KOH say their compound is more commonly used for biodiesel because it does not clump as much. They can't both be right.

Moved this text:

It is also a traditional ingredient in the making of soap, and for this
 purpose was historically obtained in an impure form by steeping wood ash in 
 water for a long period.

to the KOH entry and added a bit to this entry about the confusion of NaOH and KOH by both of them being called "lye."

As far as food poisoning, I'm stumped; the article should mention this, if only for safety reasons. As for cleaning flesh off bones...ewwwwww....but sure.

"German pretzels are poached in a boiling sodium hydroxide solution before baking, which contributes to their unique crust." This is quite simply not true, although a wide-spread misunderstanding. Sodium Hydroxide, NaOH aka E524, is always used in a room-temperature solution. This is the most common substance used for German "Laugenbrezen". One could use baking soda, NaHCO₃ aka E500, instead, and this would be used in a boiling solution. This is extremely uncommon, howewer, as the risk of injury would be considerably higher. Handling a room-temperature solution is considerably safer. A really good source - in German, alas - is http://www-pool.math.tu-berlin.de/~boerner/kulinarisches/laugengebaeck_de.php?s=begriffe. YorickDowne 18:10, 21 February 2007 (UTC)

About language and communication of ideas.

I would like to see some text here about lye. How was the substance originally created/discovered? What was it originally used for? From which base substances is lye commonly created from today...?

So often in the field of chemistry, the conversation deteriorates into a speculative maze of generalized theories of chemical interaction. I find it more educational to hear of known observations and known physical building blocks of chemicals in terms of the real hands on knowledge that a person has who works in a factory.

This genre of writing would communicate more effectively to casual readers who are interested about these guild issues. --- Rainbird 21:12, 28 Sep 2004 (UTC)

---

Just out of curiosity, is the scenario portrayed with lye in "fight club" (about the chemical lye burn) realistic? does it burn that fast? --2tothe4 20:37, 27 September 2005 (UTC)

If the burns I've seen from dry drain cleaner are an indication, then yes, it's pretty accurate. In fact, his hand probably wasn't burned enough. 64.121.2.24 00:55, 22 August 2007 (UTC)

Basic chemical data needs attention

What would be the effect of using sodium hydroxide, rather than sodium carbonate, to raise the pH of a solution after acidification with HCl? can someone please answer this question?

The sidebar on the left of the page isn't that well developed; a picture especially is nice. If you need an example try Hydrochloric acid. HereToHelp 20:38, 28 September 2005 (UTC)

Yes, it's on our list of things to do- but that list has 380 chemicals on it! The HCl page uses our standard table, this page uses someone's own design, and it needs updating. We should get to it fairly soon, since NaOH is important. Walkerma 21:09, 28 September 2005 (UTC)

I just added the proper chembox. Now only to fill in the data from the old to the new. Do you CareToHelp, HereToHelp? Wim van Dorst 21:16, 28 September 2005 (UTC).

Beat you to it. Next time just dig in. Wim van Dorst 22:16, 28 September 2005 (UTC).

Corrosive Properties of sodium hydroxide

Is anyone familiar with how long the corrosive properties of sodium hydroxide are active once water has been added? Also, once the water is evaporated from the solution, if water is added again, will it reactivate the corrosive properties of the sodium hydroxide?

One point straight away: sodium hydroxide always contains water: the commercial solid is about 15% water and is deliquescent, that is it will absorb water from the atmosphere to the extent that it dissolves in it.

In the European Union, sodium hydroxide solutions are classified as corrosive if they contain more than 2% NaOH (0.5 M), and as irritant if they contain 0.5–2% NaOH (0.125–0.5 M) (source: European Chemicals Bureau). Physchim62 19:55, 14 October 2005 (UTC)

Use in Biodiesel

My employer makes biodiesel. According to him and other internet sources NaOH is most typically in smaller operations because it is readily available in the form of Red Devil Drain cleaner. Clunping is not a problem if used with Methenol, but if Ethenol is used KOH must be substituted do to coagulation.

Highly reactive yet relatively stable?

Read the 2nd and 3rd paragraphs. Was "stable" meant to be "reactive"? Also, at the end of the 2nd paragraph: "Therefore, it should be stored separately." From what? Why? Twilight Realm 22:39, 12 October 2005 (UTC)

Use in soap

I'm guessing that in soap, it is in a very low concentration. Correct? Twilight Realm 22:46, 12 October 2005 (UTC)

• In the finished soap, it is to all intents and purposes absent, as it is consumed during the manufacturing process. Physchim62 06:31, 14 October 2005 (UTC)

--Correct, home-made soap usually contains an excess of 5% to 8% of more fat than the amount of NaOH used can saponify. In a batch of 2 lbs. of soap, you can end up using somewhere inbetween 4 oz. to 5 oz. depending on what oils you use. Each oil (palm, olive, apricot, the list goes on) has a different saponification value, so differing amounts of lye would saponify 1 oz. of olive oil and 1 oz. of palm oil.

For those trying to improve this page

Try visiting [1] and [2] for information. Twilight Realm 22:58, 12 October 2005 (UTC)

"Lime" Disambiguation

In the Related Compounds section at the side, we have Ammonia Lime (each word linked separately). I'm attempting to update links to the disambiguation page for Lime, but I don't know what Ammonia Lime is. Googling for it's turned up blanks. Is it CaO? Can someone update this when they find out? --138.38.32.84 17:47, 2 February 2006 (UTC)

They are meant to be two separate items: ammonia and lime (calcium hydroxide). Edgar181 17:51, 2 February 2006 (UTC)

Since Titanium is highly unreactive as compared to iron, copper and aluminium, why does it react with NaOH whereas iron and copper do not?

Precautions

When water is added to lye, it produces heat and will burn flesh. Why does the precautions section tell people to wash with water in case of contact with skin? Why does it suggest that vinegar will burn? This is not funny. I'm changing the text- if you have a problem with it, cite a legitimate source. Juicifer451 14:16, 15 August 2006 (UTC)

Good revision.Juicifer451 18:01, 15 August 2006 (UTC)

Thanks. This has been done now on several articles. Safety should really be a small part of the text, we can't be complete, and if there are errors .. so I axe it down. If people need safety information, they can look it up in an MSDS (the link in the chembox should be working, and otherwise, there is Wikipedia:Chemical sources). See you around! --Dirk Beetstra ^{T C} 18:05, 15 August 2006 (UTC)

Men of Honor

No reference in Men of Honor to a deleted lye scene. DavidBofinger 02:39, 16 October 2006 (UTC)

OK, I deleted it. Trivia sections are widely regarded as frivolous, and lye is hardly an obscure substance - it probably appeared in several non-deleted movie scenes! Not really notable or even amusing anyway IMHO. Walkerma 03:22, 16 October 2006 (UTC)

Men served fries doused in lye

"It was an accident, but they served these people french fries with sodium hydroxide instead of vinegar"[3] -- noosphere 22:36, 30 December 2006 (UTC)

History of Soap

The text currently reads:

Soap making via saponification is the most traditional chemical process using sodium hydroxide. The Arabs began producing soap in this way in the 7th century, and the same basic process is still used today.

I've heard this claim before, I think even in reliable sources (though I don't remember which), but as Roman, Egyptian, and apparently even mesopotamian sources mention the mixing of ashes and fat to make soap, I'm not sure what is meant. Were the arabs the first to chemically isolate Sodium hydroxide maybe? --Iustinus 02:18, 31 December 2006 (UTC)

NaOH + HCl -> NaCl + H20?

Is this worth mentioning? NaOH + HCl -> NaCl + H₂0? 71.168.108.66 21:33, 22 January 2007 (UTC)

Don't all acid+base mixtures yield a salt and water? —The preceding unsigned comment was added by 71.97.20.102 (talk) 21:16, 13 April 2007 (UTC).

No it's not worth mentioning. That is quite arbitrary.--Leiding (talk) 04:00, 1 February 2009 (UTC)

Is this correct?

Is this: [4] change from 0.2 to -2.43 by an anonymous user correct? JohJak2 09:50, 2 February 2007 (UTC)

Spencer MA "trivia" and water treatment usage

I find it odd that almost 100 people going to the hospital would be under "trivia". It is also odd that the reason for the problem was an excess of NaOH getting into the water at a municipal water treament facility, but this use is not mentioned anywhere in the article. Links:

4/26 story in Boston Globe

4/27 ban lifted article in B. Globe

Huw Powell 00:24, 2 May 2007 (UTC)

The gas released from mixing water and drain cleaner?

Hmm, I looked both here and in the drain cleaner article, but either I'm missing something, or the articles don't explain what the gas released from the reaction of common drain cleaner based on lye and water is? I think this would be interesting to know, e.g. NaOH + H2O = ??? Or is another component of commercial lye involved here, in making the characteristic gas that irritates when inhaled? -- Northgrove 00:02, 11 May 2007 (UTC)

I suspect you are thinking of sodium hypochlorite rather than sodium hydroxide. See: Sodium_hypochlorite#Cautions. Biscuittin 13:07, 4 June 2007 (UTC)

Some dry drain cleaners contain chips of aluminum. When water is added, the sodium hydroxide reacts with the aluminum, producing hydrogen gas. The reaction is energetic enough to boil the water, so much of the gas released is steam. Karl Hahn (T) (C) 13:46, 4 June 2007 (UTC)

Thanks for both of your replies! Yes, it is a very energetic reaction, so much that you have to be very careful when applying the water to the dry cleaner to start the reaction, and it basically boiled up for me like a small geyser effect. I was however not using bleach (sodium hypochlorite?), but a drain cleaner in solid form (caustic solid?), for the purpose of making the water flow better through the drain. — Northgrove 08:38, 28 August 2007 (UTC)

History

It would be nice to add the history of this compound; when was it discovered and how was it made before the modern processes were invented. Since I don't know, I'll just leave it as a "to-do" note... --Itub 07:27, 24 May 2007 (UTC)

Merge from Manufacture of Sodium hydroxide by Nelson's process

The new article just doesn't look long enough to stand on its own. I don't see more than a few sentences that could be added to this article. The information is covered quite well in #Manufacture, and the new article might have a few extra details. Thoughts? Tuvok[^T@lk/_Improve] 11:45, 20 January 2008 (UTC)

I agree...and the manufacturing process should be combined with the product itself. It is much better to streamline than make users have to access a number of pages for information on a single subject. —Preceding unsigned comment added by 146.141.15.34 (talk) 06:26, 11 February 2008 (UTC)

Agree. This is just one of a number of manufacturing processes discussed in the main sodium hydroxide article, falling under the class of "diaphragm methods." I also have a beef with the Manufacture of Sodium hydroxide by Nelson's process article itself, in that the only reference it cites is the MSDS sheet, which has absolutely nothing to say about manufacturing methods. In that light, the merger should consist of a mention of the the Nelson cell in the "Diaphragm methods" paragraph rather than a detailed description (at least until a suitable reference is found). Karl Hahn (T) (C) 16:07, 13 February 2008 (UTC)

I think sodium hydroxide and its manufacture are important enough to warrant an article, but at this point we don't have enough content to justify a set of articles (one for each process). How about moving this content over to Manufacture of sodium hydroxide, cleaning it up, and then adding in the other processes, history, major world production (locations, companies and tonnages) etc.? Wim and myself might be persuaded to work on it. Walkerma (talk) 20:51, 13 February 2008 (UTC)

I agree... —Preceding unsigned comment added by 86.18.251.148 (talk) 09:43, 21 February 2008 (UTC)

Agreed! RockRichard (talk) 05:14, 24 April 2008 (UTC)

Isn't the Nelson's process information already well-covered in Methods of production under Membrane-Cell process? --SV Resolution(Talk) 16:42, 29 January 2009 (UTC)

Washing with water

There was a line near the bottom of the page to the effect that the proper conduct when spilling sodium hydroxide on the skin is washing it off with water. This seems like a dangerous piece of misinformation, as I belive the reaction of water with NaOH is exothermic and would just exacerbate the burn. If we can find a citation I'm pretty sure the proper protocol is to use a weak acid like white vinegar to neutralize it (although I picked that up from "Fight Club" so it may be untrue). —Preceding unsigned comment added by 72.175.42.232 (talk) 02:33, 12 September 2008 (UTC)

Why would hydration with acid diluted with water be any less exothermic than with plain water? Neutralization is also exothermic. --Vuo (talk) 14:05, 13 September 2008 (UTC)

I think the assumption was that you had either spilled the solution on your hands (NaOH is almost always used as an aqueous solution), or else you had rubbed off the bulk of the solid before washing. Water will very quickly remove the bulk of the NaOH. Vuo is right, white vinegar (95% water, + 5% acetic acid) would be a little worse for heat, but for normal spills it would be good too. The good thing about water is that you can run cold water over the injury for 15 minutes. Walkerma (talk) 18:26, 13 September 2008 (UTC)

Merge with original article

Yes why not I give Positive Vote to merge with Mother Article....

pH of this substance

I would just like to know the pH of this substance. —Preceding unsigned comment added by 76.26.93.7 (talk) 02:22, 4 November 2008 (UTC)

From http://wiki.answers.com/Q/What_is_the_pH_number_of_sodium_hydroxide:

Sodium hydroxide does not have a pH number. The pH of a solution of sodium hydroxide depends entirely on the concentration of it in that solution.

Google is your friend. :) Tuvok[^T@lk/_Improve] 02:39, 4 November 2008 (UTC)

The pH is defined by the H+ concentration [H+]: 10^-pH = [H+]. The water dissociation is [H+] * [OH-] = 10^-14 and the sodiumhydroxide dissociation gos with [Na+]*[OH-]/[NaOH] = 10^-pKB. All pH values depend strongly on the themerature. I hope that helps.

The pKB given in the article is unreliable. I found a source, but I don't have access to it. Perhaps someone is so kind to look it up. Unexpected performance of solid alkaline metal hydroxides in liquid phase oxidation of 1-phenylethanol. Ben-Harush, Kfir; Wolfson, Adi; Herskowitz, Moti. Chemical Engineering Department, Blechner Center for Industrial Catalysis and Process Development, Ben-Gurion University of the Negev, Beer Sheva, Israel. Letters in Organic Chemistry (2006), 3(9), 664-667. Publisher: Bentham Science Publishers Ltd., CODEN: LOCEC7 ISSN: 1570-1786. Journal written in English. CAN 147:166017 AN 147:166017 CAPLUS Mgloede (talk) 10:17, 25 November 2008 (UTC)

pH is defined by the activity of H⁺, not its concentration, which complicates matters somewhat. The best estimates I've seen are pH = 12.73 for 0.1 M solutions and pH = 13.54 for 1.0 M solutions, from [5]. Physchim62 (talk) 11:43, 25 November 2008 (UTC)

Merge with Lye?

Shouldn't Lye be merged into this article? There seems to be some duplication of information there. --SV Resolution(Talk) 16:26, 29 January 2009 (UTC)