Talk:Sodium hypochlorite/Archive 1

Incorrect equation

from the article:

"(...) It is prepared industrially by electrolysis minimal separation between the anode and the cathode. The solution must be kept below 40 °C (by cooling coils) to prevent the undesired formation of sodium chlorate.

   3 Cl2 + 6 NaOH → NaCl + 5NaClO + 3H2O

Also the above equation is incorrect

Sodium hydroxide and chlorine are commercially produced(...)" —Precedingunsignedcomment added by Monstrim (talk •contribs) 16:33, 16 July 2009 (UTC)

What the hell? Monstrim (talk) 16:34, 16 July 2009 (UTC)

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)

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.~K04:07, 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].

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.folsom18:41, 13 December 2006 (UTC)

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)

Either way the cation should be listed first (i.e. NaClO or NaOCl) regardless of which of the two atoms in the anion is listed first. 21:28, 1 December 2009 (UTC) —Preceding unsigned comment added by76.164.35.146 (talk)

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)

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)

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)

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)

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)