Since the white residue left on drying includes sodium hydroxide, it
would be undesirable in aquaria, and so a bleach solution should not be
allowed simply to evaporate to dryness if used to disinfect tanks.
David L. McNeely, Ph.D., Professor of Biology
Langston University; P.O. Box 1500
Langston, OK 73050; email: dlmcneely-in-lunet.edu
telephone: (405) 466-6025; fax: 405) 466-3307
home page http://www.lunet.edu/mcneely/index.htm
"Where are we going?" "I don't know, are we there yet?"
----- Original Message -----
From: "Welaka T. Phishhed" <welaka75-in-yahoo.com>
Date: Thursday, June 9, 2005 3:10 pm
Subject: Re: NANFA-L-- Chlorine Bleach
> I found this . . .
> "To say that chlorine bleach does not contain chlorine is true,
> but somewhat
> misleading. True, it does not contain diatomic chlorine gas, CL2.
> It does
> contain sodium hypochlorite, NaOCl, which is one of the products
> producedwhen aqueous sodium hydroxide (caustic soda) reacts with
> Cl2. (The other
> product is sodium chloride, NaCl.) It is a very strong oxidizing
> agent.Some non-chlorine bleaches contain slightly weaker oxidizing
> agents, which
> will oxidize the colored molecules in many common stains, but not the
> robust pigments of commercial textile dyes. That's what makes them
> "color-safe." It's a trade-off: if the stain is a tough molecule
> (such as
> turmeric, the vegetable dye used to make mustard bright yellow), the
> strength of bleach required to oxidize it will also destroy the
> textile'scolor."
>
> WARREN
>
> dlmcneely-in-lunet.edu wrote:
> You're right about the calcium hypochlorite. My mistake there. But
> I
> found this
>
> http://www.inchem.org/documents/pims/chemical/pim495.htm
>
> "IPCS INCHEM is a means of rapid access to internationally peer
> reviewed information on chemicals commonly used throughout the
> world,
> which may also occur as contaminants in the environment and food.
> It
> consolidates information from a number of intergovernmental
> organizations whose goal it is to assist in the sound management
> of
> chemicals.
>
> Sodium hypochlorite
>
> Composition/Purity: Usually sold in solutions
> containing 5 to 15% sodium hypochlorite in water,
> with
> 0.25 to 0.35% free alkali (usually NaOH) and 0.5 to
> 1.5% NaCl. Solutions of up to 40% sodium
> hypochlorite
> in water are available. Solid sodium hypochlorite
> (NaOCl.5H2O) is not commercially used."
>
> All data I could find on the web discussed as liquid sodium
> hypochlorite the water solution used as bleach, not the pure
> material.
> And I found nothing that indicated that commercially available
> bleach,
> including 'Purex" brand, was prepared by mixing washing soda
> (sodium
> bicarbonate) with a chlorine source, though they might be. If so,
> then
> the white residue that bleach leaves on evaporation would be
> sodium
> bicarbonate -- which would be relatviely harmless in an aquarium.
> But,
> the labels on bottles indicate that it is "hypochlorous acid," --
> that
> is a water solution of sodium hypochlorite.
>
> So, I remain confused about solid sodium hypochlorite.
>
> David L. McNeely, Ph.D., Professor of Biology
> Langston University; P.O. Box 1500
> Langston, OK 73050; email: dlmcneely-in-lunet.edu
> telephone: (405) 466-6025; fax: 405) 466-3307
> home page http://www.lunet.edu/mcneely/index.htm
>
> "Where are we going?" "I don't know, are we there yet?"
>
> ----- Original Message -----
> From: geoffrey kimber
> Date: Thursday, June 9, 2005 2:24 pm
> Subject: Re: NANFA-L-- Chlorine Bleach
>
> > the pool stuff I have seen is calcium hypochlorite.
> >
> > I wonder if the white residue is buffers, or maybe salt?
> >
> > I searched the web and found several sites that stated that sodium
> > hypochlorite is a liquid, so I'm pretty sure it's true but not 100%
> > because who can trust the web?
> > /----------------------------------------------------------------
> --
> > -----
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>
>
> Best Wishes !
>
> WARREN
> *?-:¦:-?:*'''''*:?-:¦:-?*
> (Welaka T. Phishhed)
> WELAKA CREATIONS
> (E-BAY...photoguy6900)
> welaka75-in-yahoo.com
>
>
>
>
>
>
>
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