Ask A Scientist© Chemistry Archive

name       Alex
status     other
age        30s

Question - What will stop Bleach meaning what will neutralize bleach?
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Bleach is a 3-5% solution of sodium hypochlorite [NaOCl]. It is rapidly 
reduced by reducing agents. One reducing agent that is fast,effective, 
available, and cheap is sodium sulfite [Na2SO3] -- not sulfate [Na2SO4]. 
It is available from any swimming pool chemicals retailer. It will be 
called something like "knock down", "de-chlor" or similar trade name. It 
is used to reduce the level of chlorination in swimming pools. I use it 
myself to de-chlorinate my bathing suit after swimming.

Sodium thiosulfate [Na2S2O3] will also work. It is used in developing 
photographic film and prints. Its common name is "Fixer". It is available 
in any photographic supply store, but is likely to be more expensive than 
sodium sulfite.

In principle, ascorbic acid [vitamin C tablets] should also work. It is a 
reducing agent, but I haven't tried it myself to neutralize bleach. I have 
used it to "bleach out" certain stains in clothing, because some dyes, 
when reduced, become colorless. It works very well on certain stains.

V. Calder
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