Talk:Sodium hypochlorite

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[edit] Dilution

I could also use a little advice. If you have 40% Hypo, is that the same as 400,000 ppm?


I need advice, a 50% solution (by weight) of NAOH in water contains how many pounds of NAOH in a gallon of solution?? How many gallons of 50% NAOH solution is needed to react with 8.69 pounds of chlorine gas?? How much NACLO in a 12% solution (by weight) results??Nelsondsn 15:55, 24 January 2007 (UTC)


What do you mean by 1:5? does this mean 1 part water to 5 parts bleach? is the most effective. -Anon

No it means 1 part bleach to five four parts water is strong enough to kill bacteria.theresa knott 22:08, 6 Feb 2004 (UTC)

Now I agree : O) irismeister 18:07, 2004 Feb 13 (UTC)

A mixture consisting of one part bleach and four parts water may be referred to as a 1:4 mixture or a 1 in 5 dilution. --Jose Ramos 16:23, 21 Feb 2004 (UTC)

Right. Not and Never 1 part bleach to five parts water, as misleadingly "corrected", and only then recorrected - which the editor doing the mistake acknowledged in the history section. Happy editing - irismeister 16:51, 2004 Feb 21 (UTC)

Did you just say "Right." and then disagree?

The link to the Hazardous Chemical Database in the properties table on the left is completely wrong. That chemical's formula is C10H10O, this article is about NaClO. The proper link should be http://ull.chemistry.uakron.edu/erd/chemicals/8/7063.html. This is a gross error on the part of the author...
No it's not. Unfortunately the Hazardous Chemicals Database has changed all it's URLs. Not all the tables have been updated yet (I am about to do this one), but when they are we are removing the external links from the table, as per Wikipedia policy, to avoid this sort of problem in the future. Physchim62 21:50, 21 August 2005 (UTC)


In 2000 Clorox Corporation changed its household bleach formulation, increasing the sodium hypochlorite concentration from 5.25% to 6.00%, and calling it "Ultra Clorox". The bottle size changed from 4 U.S. quarts to 3 U.S. quarts, decreasing the mass of water being shipped and the storage space requirements, but also decreasing the total amount of sodium hypochlorite in the bottle. Most other liquid bleach brands in the U.S., including supermarket house brands, followed suit within a year, and it is now nearly impossible to find the traditional 5.25% concentration. This should be taken into account when reading older recipes for preparing disinfection and sterilization solutions. (In spite of dramatic raw materials price increases in 1999, Clorox nonetheless reported a record increase in profits the following year with the introduction of Ultra Clorox and discontinuation of regular Clorox bleach. Hmmm ...) -- Anon 16:40, 21 July 2006 (UTC)

[edit] Hypochlorite and Trihalomethanes

I put the POV banner on because of the largely blank info-box and the mention of trihalomethanes. --Kvuo 00:56, 20 August 2005 (UTC)

Please! This is NOT a POV issue. Just a lack of information. I don't understand the trihalomethane issue, nor do I understand how mentioning trihalomethanes it makes this a POV issue. Needless to say, I believe the POV banner should be removed immediately. ~K 04:07, 20 August 2005 (UTC)
No, it's not a POV issue as we usually see them in chemistry. However, the article does need some serious copy-editing to bring it into style. I am rather worried about the lack of references for its use in the chlorination of drinking water. BTW, a mention of trihalomethanes is actually quite a good warning sign for a dodgy hazards section: I've seen much worse than this one! Physchim62 21:50, 21 August 2005 (UTC)

It's all much better now, and I've learned things in the meantime. Wikipedia works! --Kvuo 23:41, 2 September 2005 (UTC)

Quite right. Despite all the chaos, the Wikipedia is definitely improving. ~K 00:53, 3 September 2005 (UTC)

Is it possible that when equal amount of sodium hypochlorite solution and cold water reacts together in the absence of heat or light, hydrogen peroxide is formed? [My email address - kc4kus@yahoo.co.uk].

[edit] Disinfection of non-cellular biological molecules

The current article is quite good for explaining the mechanism of action of how bleach kills cellular life, but how is it an effective disinfectant for biological molecules such as DNA and viruses? Sekiyu 18:11, 4 April 2006 (UTC)


Actually the mode of action, described is not correct. The scenario presented is outdated, and has since been supplanted by more plausible ideas since. But that's actually not the point. There is currently a calcium hypochlorite , sodium hypochlorite and a Lithium hypochlorite article as well as a hypochlorous acid article. The hypochlorites all produce hypochlorous acid when in aqueous soln., and the mode of action described here is the mode of action of hypochlorous acid. I will be writing a detailed section on the mode of action of hypochlorous acid including viruses, for the hypochlorous acid article. So I propose that the mode of action be at that time removed from this article and replaced with a link to the mode of action of hypochlorous acid, once it is written. James.folsom 18:41, 13 December 2006 (UTC)

[edit] Element Order

I have a problem with the way it's presented. Shouldn't it be NaClO? (the hypochlorite ion is ClO with a -1 charge most commonly...). Permission to change? --STufaro 16:45, 24 June 2006 (UTC)

Don't bother, I have seen the hypochlorite ion writen as OCl- and as ClO-.Kyanite 05:37, 22 November 2006 (UTC)

[edit] Toxicology

We need some toxicology info. I'm going to dig some up, unless someone beats me to it :) 70.104.97.109 22:58, 11 August 2006 (UTC)

[edit] Aqueous acid with alkaline pH?

Under the heading Mechanism of action this article currently describes the aqueous solution of sodium hypochlorite to be substantially composed of hypochlorous acid. It is difficult to understand that such a diluted solution as 0.5 weight percent (or about 10 volume percent of a stock solution of household bleach in water) exhibits an alkaline pH if it dissociates into an acid. This is a peculiar enough characteristic to merit a brief explanation in the article. --Zymatik 16:40, 9 October 2006 (UTC)

Sodium hypochlorite is basic because the hypochlorite ion (ClO-) (which is the conjugate base of a weak acid, and therefore a strong base), picks up H+ from the solution to form HClO. --Spoon! 02:00, 8 March 2007 (UTC)

[edit] Confusion with calcium hypochlorite

Whoever wrote:

High-test hypochlorite (HTH) is sold for chlorination of swimming pools and contains approximately 30% sodium hypochlorite. The crystalline salt is also sold for the same use; this salt usually contains less than 50% of sodium hypochlorite. However, the level of "active chlorine" may be much higher.

is confused. These statements describe calcium hypochlorite, and should not be in this article. "Active chlorine" should be "available chlorine", an industrial rating giving the relative performance in chlorinating power compared to an equal mass of elemental gas chlorine. It does not directly relate to the purity of the product. Richard J Kinch 06:40, 18 October 2006 (UTC)

[edit] long term storage

"Household bleach sold for use in laundering clothes is a 3-6% solution of sodium hypochlorite at the time of manufacture. Strength varies from one formulation to another and gradually decreases with long storage."

What is the mechanism by which the concentration of household bleach gradually decreases with long storage? What are the byproducts? Does it just get weaker, or is there any other problem with the remaining solution? What can be done to store bleach as long as possible in the most stable way possible? For example, if a large container of bleach were divided immediately into smaller, full containers, would the full sealed containers keep their strength for a longer period of time than one large, occasionally opened container? 69.87.194.77 00:58, 25 October 2006 (UTC)

The NaClO outgasses oxygen leaving NaCl in solution. Pool chlorinator weakens substantially from this process in a matter of weeks. Old bleach is weak bleach. This is somewhat inhibited by high pH, so most products have a lot of NaOH added into them. Richard J Kinch 05:56, 26 October 2006 (UTC)
So, as it weakens, it turns into harmless salt water? Fresh 5% bleach is a pale lime yellow-green. This is characteristic of Sodium hypochlorite solution? Can the concentration be roughly judged by the fading color -- when it is fully depleted, will the solution of remaining salt water be clear? 69.87.202.55 00:23, 27 October 2006 (UTC)
I would expect the color to reflect concentration, but color may also be due to impurities. This would be easy to test, by leaving a sample out in the sun for a few days. Dilute with distilled water and test with OTO dye from a pool store to measure strength.
It's not just harmless salt water. It contains a lot of NaOH. Richard J Kinch 06:51, 28 October 2006 (UTC)
So, it reaches a long-term equilibrium with the oxygen partial-pressure in the vapor space? So, minimizing vapor space makes it last longer? (And opening the container as seldom as possible.) Common bleach is sold commercially in #2 plastic bottles. What are relative dis/advantages of #1 PET/PETE vs. #2 HDPE? vs. glass container? Seems like minimal oxygen permeability is desireable? 69.87.202.55 00:23, 27 October 2006 (UTC)
The pool store products have to be sold with pressure-venting caps. I don't know what the effect of not venting would be. Assuming the container didn't rupture or diffuse the gas, the oxygen may just dissolve into the solution. Richard J Kinch 06:51, 28 October 2006 (UTC)

[edit] Mixing

The Clorox container says nothing about shaking before use. Does the 5-6% commercial solution separate over time into fractionated layers, should it be mixed before use? As the solution weakens over time, does the top layer of resulting salt water tend to stay floating on the top (slowing further weakening) or sink to the bottom (promoting further weakening by self-stirring)? 69.87.202.170 12:23, 31 October 2006 (UTC)

[edit] Spills

It would be good for the article to include some suggestions about best ways to clean up spills of various sizes. And/or specific links to such info. It seems like water dilution would be helpful to clean up smaller amounts -- but with larger amounts, you would just have an ever-larger problem, of still-potent liquid? Are all types of plastic gloves appropriate protection, or are some vulnerable to being dissolved by the Sodium hypochlorite solution? 69.87.202.55 00:36, 27 October 2006 (UTC)

Also, sodium thiosulfate (hypo) is an instant chlorine neutralizer, great for getting that chlorine odor off your hands. 1 teaspoon in a quart of water, kept in an old liquid soap pump, makes a good hand rinse. Richard J Kinch 06:57, 28 October 2006 (UTC)
We don't usually quote spillage control measures for the simple reason that most of them are identical: "large amounts of water"! The International Chemical Safety Cards quoted in the article guard aginst using absorbants for bleach spills, probabaly because of the risk of forming small quntities of dioxin. Thiosulfate is only useful for very small splills. Physchim62 (talk) 12:59, 30 October 2006 (UTC)

[edit] Slippery on skin

I spilled some 6% Clorox on my hands. Rinsed off immediately. But skin had a slippery feel, that was hard to wash off. What is happening? 69.87.202.55 00:46, 27 October 2006 (UTC)

My guess- you're making soap from your skin oils. Bleach is alkaline, and the recipe for soap is fat/oil/etc + alkali. Good idea to wash it off.--Smokefoot 01:03, 27 October 2006 (UTC)
Household blean contains lye (NaOH) as a stabilizer. This defats your tissues and turns you into human soap. Rinse for a few minutes, then apply a hand lotion. Richard J Kinch 06:57, 28 October 2006 (UTC)
This is a common problem that I teach to my students. If you wash the bleach off quickly enough you shoud not have any further irritation. If you have irritation, see a medical practioner (although hand oil works quite well as well for very minor burns, which are by far the most common). Your medical practioner will almost certainly have experienced the same effect when he or she did basic Chemistry as part of their medical degree (medics are not known for being the most careful in a chemical laboratory!) The explanation is as given above: you have turned your skin oil into soap! Physchim62 (talk) 12:54, 30 October 2006 (UTC)

[edit] Mechanism of action

I'm nearing completion of my edits of the hypochlorous acid article. I will be adding a discussion of the mechanism of action there. It is more comprehensive than the one contained here. The explanation presented here has since been shown to be in error, but I have however cleaned up the language and provided a reference to the article where the idea was originally proposed. I will not do anything further, and will leave it to the community to decide how to deal with it.James.folsom 21:07, 30 December 2006 (UTC)

The mechanism of action was incorrect. Ask any chemistry teacher or professor, sodium hypochlorite, a soluble salt, completely dissociates in water. The hypochlorite anions react with water to produce a minuscule amount of hypochlorous acid and hydroxide anions. This is defined by the Kb equation for the hypochlorite anion. TheLiberalTruth 21:14, 10 May 2007 (UTC)

I suspect they were confusing NaOCl, which is ionic and completely dissociates, with HOCl, which is a weak acid and therefore only partially dissociates. Thanks for fixing it. Walkerma 21:16, 10 May 2007 (UTC)
The mechanism of action is still wrong, and the ratio of OCL to HOCl is pH dependent. With significant amounts of HOCl being produced at neutral and lower pH. Since this topic continues to degenerate into inaccuracy, I will remove it and provide a link to the more accurate information, provided there is no objection. James.folsom 21:26, 23 August 2007 (UTC)

[edit] Hypochlorite or Hypochloride?

Are sodium hypochlorite and sodium hypochloride the same thing? I've seen both referred to as bleach. When I visited the American Chemical Society http://www.chemistry.org/, they have no listing for hypochloride, only hypochlorite. Is hypochloride a misnomer? BTW, they list the chemical formula for sodium hypochlorite as NaOCl, not NaClO. BCreegan 10:13, 9 January 2007 (UTC)

Hypochloride is a misnomer. The suffix –ide should only be used when a single element forms part of the anion, not two as here. For the formula, both are used, I will investigate as to which is really preferable. Physchim62 (talk) 15:42, 9 January 2007 (UTC)
I believe NaOCl is preferable because it indicates the electron sharing (or giving in the case of sodium) correctly, i.e if sodium was more electronegative or oxygen less electronegative, it would be a covalent bond that would look like: Na-O-Cl. (I hope that makes sense). --Mark PEA 19:18, 5 June 2007 (UTC)

[edit] Spam

I deleted some spam. Someone inserted irrelevant commentary regarding the Clorox brand of bleach.

142.167.140.186 01:14, 14 May 2007 (UTC)

Under Uses the second paragraph says these chlorinated byproducts of sanitizing surfaces are also harmful.. Does this mean harmful to ingest, to the surface, to the taste, or to the fermentation process? User:Wayne-PhyChemMth 15:54, 21 May 2007 (UTC)

[edit] Valid resource?

Having consulted the resource cited on the dangers of mixing sodium hypochlorite with various substances, I'm not so sure it's a very good resource. The information is scarce and the page is clearly nonprofessional. Also, the definition of a catalyst was not specific about the catalyst not being consumed, and referred to the reaction between sodium hypochlorite and hydrogen peroxide as catalytic, when the equation provided showed the sodium hypochlorite becoming sodium chloride, which wouldn't be catalytic. This will still need to be cited, but I can't find a decent resource that contains the information. 141.156.232.115 21:21, 13 August 2007 (UTC)

[edit] Comparisons for industrial use against chlorine?

Could anyone do a comparison against chlorine? Wastewater treatment plants are being forced to change over to sodium hypochlorite due to chlorine being more of a terrorist target. Sodium hypochlorite is also noted as being more expensive Thanks! Kieranmullen 13:43, 14 August 2007 (UTC)

[edit] evaporating sodium hypochloride

hello people

Dom is my name i'm a Butcher and have recentley started a new job in a meat works.

We have this machine which is basically is a boiler ,we have vacum packiging bags which after they have been sealed pass through this boiling water and shrink the bags at the end of the day the person that operates this machine leaves an hour before me.

So he proceeds to clean this machine by pouring sodium hypochloride soloution into the water and letting it boil for 15 minutes ,then pouring the remaining water/hypo out and wiping it down, the result is a nice clean machine but at the same time fills the factory with fumes and makes me feel suprisingly sick , noone else in the factory seems to be botherd by it or maybe they don't want to say anything in fear of losing thier job but it really affects me.

So if anyone could tell me weather this is harmful on unhealthy i would greatly appreaciate some info because i won't be able to bear it much longer the bottom line is i'm looking for some info that will make my boss see its not good and make this operater get a brush and scrub it the old fachioned way instead of taking the easy way.

Best regards D Hart Sydney Australia email:dominichart83@yahoo.com.au —Preceding unsigned comment added by 220.233.172.193 (talk) 00:30, 20 January 2008 (UTC)


It's chlorine gas that is being released, it's considered toxic. I would think that would be some kind of violation. I would suggest that boiling is unnecessary to cleaning process. James.folsom (talk) 23:11, 30 January 2008 (UTC)