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Old 05-28-2011, 03:07 PM   #11
emjay's Avatar
Jan 2011
Toronto, Ontario
Posts: 12,792
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Originally Posted by rico567
(NB: never, ever mix vinegar directly into bleach, or you will have the same experience as the British Army that morning in 1915 when the Germans used chlorine gas on them at Ypres....)
Never heard of that before, and quickly figuring out the actual chemical reaction, it seems more myth than reality.

Sodium hypochlorite (bleach) and acetic acid (vinegar) SHOULD react to form hypochlorous acid and sodium acetate, the former probably being responsible for the enhanced disinfectant powers.

[sodium hypochlorite + acetic acid → hypochlorous acid + sodium acetate]

In fact, almost any acid would seem to simply produce its sodium salt + hypocholorous acid.

Speaking of sodium "salt" though, it often brings to mind table salt, NaCl (sodium chloride) which interestingly, despite sounding perhaps the most harmless also happens to be the main exception and why I said ALMOST any. Since it requires the chloride ion, it obviously can be produced with simple HCl, hydrochloric acid (aka muriatic acid):

NaClO + 2HCl → NaCl + H2O + Cl2
[sodium hypochlorite + hydrochloric acid → sodium chloride + water + chlorine (gas)]

So... keep the pool acidifiers and water softener regenerators away from the bleach

And for the last part of today's science class, just for the hell of it, might as well tackle another misconception: Bleach + ammonia (NH3), often said to also produce chlorine gas.

NaOCl + NH3 → NH2Cl + NaOH

Clearly, no chlorine gas. But in English...

[sodium hypochlorite + ammonia → chloramine + sodium hydroxide (lye aka caustic soda)]

But just because there's no chlorine gas doesn't make it safe. Lye is a pretty caustic substance, and in heavy enough concentrations can be pretty dangerous.

And chloramine, while a liquid at room temperature, will produce fumes if in an adequately concentrated solution which will have very similar toxic effects to chlorine gas. In the continued presence of bleach (almost a given), it will continue to react to produce a few other, similarly-acting chemicals. So, while it technically may not produce chlorine gas, it's still a very stupid thing to do.

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Old 05-29-2011, 03:57 AM   #12
trigger's Avatar
Aug 2010
Posts: 629
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emjay, I think you're neglecting the role of water in those formulas. Neither bleach nor ammonia comes water free in household products. Proton exchange plays an important role in all those reactions.

Needless to say, mixing bleach is a dangerous proposition. It is not to be trifled with. It can, however, lead to the evolution of elemental chlorine when mixing with acids or bases under the right conditions. The kicker is where the equilibrium lies. Mixing bleach with NH4+, the species found in aqueous solution, will in fact lead to the production of some chlorine gas, with the amount being dependent mainly upon the ratios present.
The power to tax, once conceded, has no limits; it contains until it destroys. I was not joking when I told them to dig into their own pouches. It may not be possible to do away with government sometimes I think that government is an inescapable disease of human beings. But it may be possible to keep it small and starved and inoffensive and can you think of a better way than by requiring the governors themselves to pay the costs of their antisocial hobby?

R. A. Heinlein

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Old 05-29-2011, 05:53 AM   #13
May 2011
Waterford, NJ
Posts: 61
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Originally Posted by KFBass View Post
if you do, just pee on a rag and breathe through that! That's what the Canadians did while the french and british lines fled!
Huh... That explains a LOT!

I keed I keed...

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