Talk:Sodium hydroxide/Archive 1

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)

Doing acid base chemistry is not advised on severly irritated skin. Leave this section alone. Water will dilute and remove the NaOH and without jacking the pH of the skin all over the place. --Dwdockter (talk) 21:06, 28 July 2009 (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)

Anhydrous sodium hydroxide does exist and is sold by several manufacturers. As to the question about the corrosive properties, the solution will keep its corrossive properties as long as the sodium and the hydroxide ions are there. Sodium hydroxide solution in a sealed container would not lose it's corrossive properties even after hundreds of years. However, if it is exposed to air it may pick up CO2 and form sodium carbonate. It will also attack various glas and some metals containers, thereby the chemical (including corrosion) properties would change. Harting (talk) 09:39, 24 June 2009 (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. Clumping is not a problem if used with Methanol, but if Ethanol is used KOH must be substituted in order to coagulate.

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)

Well what seems to be meant is that it will react with many things readily, but if stored properly it will not decompose. Stored properly it will remain intact till the end of the universe pretty much. Other compounds decay no matter what because it is thermodynamically favorable.

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?

Titanium is not highly unreactive; it is actually highly reactive, as well as aluminum. Sodium hydroxide can dissolve the amphoteric coating on titanium and aluminum, allowing the metals to react with water and produce hydrogen gas. --Chemicalinterest (talk) 13:54, 21 June 2010 (UTC)

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)

In answering the original question: Washing skin exposed to lye is to be done with a large amount of water, so as to dilute the base and reduce its strength (while also removing the lye physically from the skin). But I approve of the revision; I'd rather people look this up on the MSDS sheet, the link to which being provided above by Beetstra. 71.112.40.73 (talk) 04:08, 7 April 2009 (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)

Not worth. But not all yield water though... NH₃ + HCl -> [[NH₄Cl]] —Preceding unsigned comment added by 118.100.20.192 (talk) 07:07, 21 December 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)

I don't know if the actual number is correct, a literature review turned up nothing when I looked. However the number should definitely be negative by the following reasoning:

in aqueous solutions [Na+][OH-] >> [NaOH] (strong base, almost completely dissociated) therefore Kb = [Na+][OH-] / [NaOH] >> 1 so log(Kb) > 0 and pKb = -log(Kb) < 0

An actual literature reference would be nice though. Harting (talk) 10:49, 25 June 2009 (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)

I make homemade soap using pure sodium hydroxide and distilled water as part of the process and there is a strong-smelling gas/fume released which is irritating to eyes/nose/lungs. I don't know chemically what it is but this question is still unanswered.

Sodium hydroxide fumes burning your nose. --Chemicalinterest (talk) 13:47, 21 June 2010 (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)

Merge with Chloralkali process: Sorry to comment a second time, but this is more than a year later, and I was apparently unaware of this more general article last year. The sodium hydroxide article itself shouldn't get cluttered up with the details of all of the manufacturing methods - there are quite a few. I believe that the Nelson process is just one specific example of the chloralkali process, is it not? Walkerma (talk) 03:43, 13 March 2009 (UTC)

What's holding up this merger (with the main article, not the Chloroalkali process)? The vast majority favors it. How does it get done? Wikiuser100 (talk) 05:19, 12 June 2010 (UTC)

Agree. People probably won't do it. You have to copy the info out of this article, paste it in the new article, and nominate the old article for deletion. --Chemicalinterest (talk) 13:48, 21 June 2010 (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)

Sodium hydrogen carbonate would be good too. It neutralizes the lye to form much less basic sodium carbonate. And when so much water is washed onto sodium hydroxide, the heat is just washed away, so it wouldn't burn. --Chemicalinterest (talk) 12:35, 12 May 2010 (UTC)

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)

What is the reaction between the Sodium Hydroxide and Pottasium Nitrate.?

Currently we are using the reaction of sodium Hydroxid & Pottasium Nitrate at 555 deg cel. It is used to clean the surface after Natural diamond is cut into 2 part with LASER. The LASER causes formation of graphite layer on the surface.

Need some alternate Solution for the process.Nitinsomkuwar (talk) 10:14, 16 January 2009 (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)

See Talk:Lye#Anti-Merge: Not all Lye is NaOH --Dr DBW (talk) 02:22, 13 October 2009 (UTC)

Use of NaOH in the production of High-fructose corn syrup and contamination with mercury

Since there appears to be a contention that the NaOH used for the production of High Fructose Corn Syrup is contaminated with mercury, would it be sensible to make reference to that here? Could someone do this? (Ref: Environmental Health article by Dufault, 2009, see http://www.ehjournal.net/content/8/1/2#B13) Or a reference to another article that might address this subject Is this likely, unlikely. What would be the nature of the mercury contamination. Is it possible to identify the manufacturers who use the chloralkali process that involves mercury as a cathode?

PastorRich (talk) 09:59, 20 June 2009 (UTC)

Atmospheric CO2 scrubber

What does the last sentence "One example is treating calcium hydroxide with sodium hydroxide and potassium hydroxide to form Soda lime." have to do with scrubbing CO2? Sodium hydroxide "scrubs" CO2 by forming sodium carbonate (2NaOH + CO2 -> Na2CO3 + H2O), which is less soluble than sodium hydroxide. Therefore one often finds sodium carbonate crystals in old sodium hydroxide solutions that have been exposed to air. Harting (talk) 09:14, 22 June 2009 (UTC)

Yes, that needs explaining more. The reason that you use soda lime in the lab as a CO₂ scrubber is that it is not deliquescent, so it will stay as a solid in your tube. It's also less corrosive (but not by much). Physchim62 (talk) 11:04, 22 June 2009 (UTC)

There is more information about this topic in the soda lime article, maybe a simple reference to soda lime, rather than a detailed explanation would suffice. After all the Sodium Hydroxide is not the actual CO2 absorbing agent in the soda lime case. Harting (talk) 09:19, 24 June 2009 (UTC)

GA Reassessment

This discussion is transcluded from Talk:Sodium hydroxide/GA1. The edit link for this section can be used to add comments to the reassessment.

This article is being reviewed as part of the WikiProject Good Articles. We're doing Sweeps to go over all of the current GAs and see if they still meet the GA criteria. So I will be assessing the article.Pyrotec (talk) 21:57, 23 June 2009 (UTC)

I'd say this is not a good article. Assertions are not adequately referenced. "Uses" section should be reorganized thematically, and ordered by importance. General or trivial uses should be minimized or removed; it is impossible to list them all. Many points raised are common to sodium and potassium hydroxides, not specific to this compound. Safety section should skip preamble. WP:CHEM style guide should be considered (WP:CHEMMOS). See hydrochloric acid for inspiration. --Rifleman 82 (talk) 16:20, 25 June 2009 (UTC)

Assessment

This is quite a reasonably comprehensive article, however it lacks WP:verification in a substantial number of sections. The article is only graded as a B-class article by WP:Chemicals, which I consider to be an appropriate rating. I'm therefore delisting this as a GA.

Once the article has been brought up to standard by adding suficient references and in-line citations, it can be renominated got GA-status at WP:GAN.Pyrotec (talk) 18:57, 26 June 2009 (UTC)

"however, only the hydroxide ion is basic"

Does anyone disagree that lead-para sentence is complete nonsense? One could instead say that the sodium ion itself is the common component of such bases as sodium hydroxide, sodium hydride, sodium (bi)carbonate, or elemental sodium if one discounts the initial hydrogen product: it is the sodium ion and its effect on the hydroxide/hydronium ion balance that matters, not which salt was dissolved to produce it, and such solutions are often referred to as sodium hydroxide solution even if that's not what happened.

The sodium cation is largely nonreactive, that explains how it can produce "salts" with very basic anions such as hydroxide, amide or hydride. As a metal cation, the sodium cation is Lewis acidic, but only very weakly. The basicity of sodium hydroxide follows from its hydroxide content only. That is the specie that affects the basicity of a solution. Your example pretty much proves itself wrong: hydroxide, hydride and carbonate have very different basicities. Carbonates react with overt acids only, hydroxides cannot deprotonate alcohols, but hydride can do that. --Vuo (talk) 15:00, 19 September 2009 (UTC)

Questionable external link

Just followed http://www.sodiumhydroxide.org/ to have a look. Don't see why it is linked, it has a couple of paragraphs on sodium hydroxide and that is it, no links to further information etc and nothing beyond what has already been covered on this wiki page. --Dr DBW (talk) 02:20, 13 October 2009 (UTC)

Since no replies etc, going to remove the link. --Dr DBW (talk) 22:16, 9 November 2009 (UTC)

pKb?

What's the basicity of this? When talking of base, we want pKb! pKa is not accurate when measuring a base! —Preceding unsigned comment added by 118.100.20.192 (talk) 07:10, 21 December 2009 (UTC)

Minimum Concentration to be labelled Corrosive

I have reverted the edit by 202.40.137.201 (05:44, 30 June 2010) regarding the minimum concentration of a NaOH solution for it to be labelled corrosive. It was changed from 0.5M to 1.5M with no reference or reason. I have changed it back, but also with no particular reference or reason, other than the change seems a bit fishy, and Physchim62's statement further up this talk page. Perhaps someone with more knowledge can provide a proper citation. Please don't change it back to 1.5M without at least citing something. Colin S (talk) 16:26, 15 October 2010 (UTC)

Merge with original article

Yes why not I give Positive Vote to merge with Mother Article.... yes the water w/t coustic soda is portable for drinking,it needs more good process and this part of my experience today. —Preceding unsigned comment added by 121.96.203.195 (talk) 08:42, 2 December 2009 (UTC)

K_sp = ?

What is its solubility product? Thank you. JKeck (talk) 03:15, 16 November 2010 (UTC)

Ksp is usually only used for poorly soluble compounds. --Rifleman 82 (talk) 03:42, 16 November 2010 (UTC)

Is the article Solubility product not properly linked?Petergans (talk) 22:41, 29 November 2010 (UTC)

Reactions

Two important reactions are missing. 1. The reaction with atmospheric CO₂. When using NaOH solutions in analytical chemistry they have to be protected, e.g. by a soda-lime guard tube. 2. Reaction with glass. Glass acts as an acid and is attacked by alkaline solutions. Hence the use of plastic containers to store the stuff.

It is very frustrating to find that such elementary chemistry is missing from a candidate for GA status. Petergans (talk) 22:53, 29 November 2010 (UTC)

There is a serious dilemma at the core of this section: the reactions described are those of the hydroxide ion. The presence of sodium is immaterial unless a solid product is formed and even then KOH might undergo the same reaction. A statement such as "Sodium hydroxide reacts readily with carboxylic acids to form their salts" is nonsensical when the compounds are in solution. There is also a laxity of language throughout this article: no distiction is made between NaOH(s) and NaOH(aq). Petergans (talk) 09:00, 1 December 2010 (UTC)

Wold War I poison gas?

An article I read stated that lye gas was used as a chemical weapon in WWI. Don't know if it is true, but if it is, it should probably be in the Uses section... Buburuza (talk) 18:58, 14 December 2010 (UTC)

Maybe you have confused something, since it wouldn't make a good chemical weapon. It is corrosive but not toxic or volatile. More effective conventional weapons existed and were widely used at the time. --vuo (talk) 20:12, 14 December 2010 (UTC)

table of std reagents

Can we include a table of properties of std reagent grades ? eg, 40% wt/wt and 50% wt/wt, which are hard to covnert to molarity unless you have the density (thinking of something similar to hte table in the crc handbook, concentrative properties of aq solutionsCinnamon colbert (talk) 14:40, 21 September 2011 (UTC)

Very high views

This is a 100,000+ per month article! TCO (Reviews needed) 17:00, 31 December 2011 (UTC)

Hazards

More content should point to the dangerous characteristics of NaOH. — Preceding unsigned comment added by Robfwoods (talk • contribs) 08:32, 25 March 2012 (UTC)

• The safety section at the bottom of the page isn't enough?--E8 (talk) 19:32, 25 March 2012 (UTC)

Is Pubchem, Chemspider, CAS etc. reliable sources?

If so then Pubchem says that the IUPAC name of sodium hydroxide is sodium hydroxyde (Link). Also these websitse lists a number of synonyms for Sodium hydroxide.→Vanischenu^TM 16:55, 1 June 2012 (UTC)

• The term "hydroxyde" is not found on that page you linked, though it is listed in the descriptors as a non-English synonym.--E8 (talk) 17:04, 1 June 2012 (UTC)

Oh! I am sorry. I have a spelling mistake there. Actually, I intended to write the IUPAC name of sodium hydroxide is sodium hydroxide. It happened because I usually write hydroxyde (though it is a mistake)

However the correct IUPAC name is written in the section IDENTIFICATION/Compound information/Descriptors/IUPAC name.(the same link). Can it be used? I put this in because in this article, a citation is demanded for the IUPAC name. And another one for the only synonym listed here. If these sites are reliable, then one could be able to satisfy the citation needed template of a large number of compounds.Vanischenu m^Talk 08:19, 4 June 2012‎ (UTC)

This question applies to all chemical compounds in general and hence, I think, that it should be moved to Help desk. Manual of style does not explain this. Hence the info obtained can be added ot it.Vanischenu m^Talk 00:12, 12 June 2012 (UTC)

Standard Enthalpy

Standard heat of formation is listed in table in wikipedia article Standard Heats of Formation as 426 kJ/mol while this wikipedia article on Sodium Hydroxide claims it is 735 kJ/mol. Both can not be right. I highly doubt 735 is correct.71.31.146.16 (talk) 07:04, 20 June 2012 (UTC)

table of standard solutions with molarity etc

I needed to know the molarity of a 40% w/w solution, very hard to find - CRC concentrative prop solutions best ref — Preceding unsigned comment added by 68.236.121.54 (talk) 14:30, 10 July 2012 (UTC)

If you can find a value of the density (or specific gravity or specific volume), the molarity is easily calculated. Dirac66 (talk) 15:21, 10 July 2012 (UTC)

Physical properties

The following requires verification and insertion into the Chembox:

• enthalpy of solution for aqueous dilution is −44.45 kJ/mol
• standard enthalpy of formation (ΔH_f^O) of anhydrous solid NaOH is −425.61 kJ/mol.

--E8 (talk) 21:26, 9 November 2012 (UTC)

Sodium hydroxide monohydrate

Should this have its own page, or just greater mention here (subjection of the same name)? GScholar turns up 191 hits, so there is coverage to warrant attention.--E8 (talk) 21:30, 9 November 2012 (UTC)

concentration of solutions

Surely the availability of various concentration solutions is a given and needs no verification. It may be that this statement about concentration is completely unnecessary. N. Barnett, Username: ATeacher 18th November 2012. 11:36 GMT/UTC

Bar Soap

It's apparently in soap bars. That should obviously be in the uses. And, health risks, and benefits would be nice if anyone's up for researching it.--97.117.164.195 (talk) 00:12, 19 November 2014 (UTC)

Assessment comment

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Last edited at 07:32, 10 June 2011 (UTC). Substituted at 06:26, 30 April 2016 (UTC)

Refs on hydrates

An editor complained that the main ref for the hydrates section was from 1893 (Pickering). However, that article is very thorough and is still the main reference for this topic. I had already refernced several recent articles by Giauque and others, who used much more precise equipment and measured many more parameters, but did not change Pickering's structure of the solubility diagram, and only made small corrections to the numbers. I used these more precise numbers wherever I could. --Jorge Stolfi (talk) 10:36, 2 May 2017 (UTC)

Solubility in ethanol

The literature seems to be unreliable about the solubility of NaOH in EtOH. Some refs say that it is very small, others that it is fair. It may be that the former consider anhydrous NaOH and EtOH, while the latter actually refer to NaOH·H2O and/or hydrated EtOH (e.g. 92.8% EtOH by mass). Could someone please sort this out? --Jorge Stolfi (talk) 10:50, 2 May 2017 (UTC)

Oil sand extraction

Hi. Sodium hydroxide is used in oil extraction from oil sands. Shouldn't it be incorporated? RhinoMind (talk) 07:07, 28 June 2017 (UTC)

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pK_b (or pK_a) value

The InfoBox currently has "Basicity (pKb): -0.56 (NaOH(aq) = Na+ + OH–)[6]"

The reference cited in the InfoBox gives pK_b = 15.76 for water, and –1.76 for the hydroxide ion.

On Quora various posts state that, if NaOH is viewed as a base, its pK_a value could be 13.8 or 14 or 15.7.
If pK_a + pK_b = pK_w = 14 (at 25 °C or so), then where does the value of –0.56 come in?

• Is the value of pK_b = –0.56 justified?
• Does some 'convention' or condition (temperature?) need to be stipulated?

—DIV (1.129.106.124 (talk) 12:13, 24 August 2019 (UTC))

Archive post on pK_b. — Preceding unsigned comment added by 1.129.106.124 (talk) 12:15, 24 August 2019 (UTC)

Lethal Dose Values

Why is it that the LD50 value is below the Minimum Lethal Dose value? There is clearly a conflict here. No average can ever be beneath it lowest member's value. The lowest lethal dose(LDLo) is mentioned here as 500 mg/kg Yet the median average for lethal doses(LD50) is 40 mg/kg : that's 92% & 460mg/kg Lower than the lowest possible established lethal dose. You can't get an average that is lower or greater than the max or min of a set because the definition of an average is constrained by the set itself. Hoping that this can be resolved. The lethal dose of sodium hydroxide is relevant because it's quite useful and it's equally relevant to know a realistic exposure limit for drain-clogging, balloon-making and general handling. Especially as a chemist. Thanks!

Error - The Solvay process suplanted the Leblanc process

"This process was superseded by the Solvay process in the late 19th century, which was in turn supplanted by the Leblanc process and then chloralkali process which is in use today."

Should read something like ...... This process was superseded by the Leblanc process in the 19th century, which was subsequently supplanted by the Solvay process and then the chloralkali process, which is in use today. 2A00:23C6:B195:401:95A:BF0D:B389:2CCE (talk) 23:36, 23 February 2023 (UTC)

Reaction with Glass

Might want to add that I found that a weak acid (lemon juice) is effective in reversing the effect it has on glass lab containers. This is after I tried cold water, hot water, MC2 (a solution of bleach, NaOH, NaCO3, etc), and dish washer. Those should be cautious if cleaning a hot glass surface with a solution containing NaOH as well. MattL9 (talk) 21:58, 22 May 2023 (UTC)

vapor pressure for NaOH is about 10 000x too high

The vapor pressure on this page is that for NaOH solution... which is mostly water, NOT NaOH. The vapor pressure given is basically the vapor pressure of water. The vapor pressure of NaOH is about a million x lower 147.231.120.7 (talk) 15:07, 23 August 2023 (UTC)