April 03, 2020, 08:01:55 PM
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Topic: Shelf Life of Calcium Hypochlorite Bleaching Solution?  (Read 229 times)

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Offline Failingeverything

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Shelf Life of Calcium Hypochlorite Bleaching Solution?
« on: March 18, 2020, 11:54:25 PM »
Probably an easy question for someone, but...

I'm confused about what happens when calcium hypochlorite is mixed with water. 
I understand this makes a bleaching solution suitable for disinfecting water.
I think I understand that this mixed solution becomes hypochlorous acid.

Questions:
How long does the calcium hypochlorite solution continue to act as a bleach, shelf life?
Does this become a storable liquid bleach?
What does the solution become when the chlorine or hypochlorous acid become inert?

Offline chenbeier

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Re: Shelf Life of Calcium Hypochlorite Bleaching Solution?
« Reply #1 on: March 19, 2020, 06:02:04 AM »
The solution is stable, because Cleaners based on it are sold in the market. The solution dies, if it is mixed with other cleaners, especially acid ones. Chlorine can be developed.

Offline Failingeverything

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Re: Shelf Life of Calcium Hypochlorite Bleaching Solution?
« Reply #2 on: March 20, 2020, 01:09:48 AM »
Sodium hypochlorite liquid bleach is definitely in stores, but I have not found calcium hypochlorite solutions in stores.

I have only found calcium hypochlorite in powder form.

Offline Borek

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Re: Shelf Life of Calcium Hypochlorite Bleaching Solution?
« Reply #3 on: March 20, 2020, 04:33:55 AM »
It is very difficult to predict shelf life of such solutions as it depends on many factors - temperature, material of the bottle, purity of water used to prepare the solution and so on.

As far as I am aware commercial bleach has pH increased by added NaOH, that makes the solution more stable and substantially slows down hypochlorite decomposition. When you dissolve the calcium hypochlorite there is no additional raise of the pH and teh decomposition starts immediately. That still means it should probably work OK for several days.

When left open these solutions will slowly release chlorine and absorb CO2, in the end you will be left with just carbonates.
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Offline Corribus

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Re: Shelf Life of Calcium Hypochlorite Bleaching Solution?
« Reply #4 on: March 20, 2020, 09:15:04 AM »
You can tell by smell. After several months, an old bottle of bleach smells like... well, nothing.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline Failingeverything

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Re: Shelf Life of Calcium Hypochlorite Bleaching Solution?
« Reply #5 on: March 21, 2020, 03:50:21 PM »
It is very difficult to predict shelf life of such solutions as it depends on many factors - temperature, material of the bottle, purity of water used to prepare the solution and so on.

As far as I am aware commercial bleach has pH increased by added NaOH, that makes the solution more stable and substantially slows down hypochlorite decomposition. When you dissolve the calcium hypochlorite there is no additional raise of the pH and teh decomposition starts immediately. That still means it should probably work OK for several days.

When left open these solutions will slowly release chlorine and absorb CO2, in the end you will be left with just carbonates.

Thank you for this answer Borek.  Very helpful!

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