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Author: Subject: Confusing hydrogen peroxide label.
Chemgineer
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[*] posted on 24-6-2023 at 07:42
Confusing hydrogen peroxide label.


I have bought a couple of 1 litre bottle of hydrogen peroxide off amazon in the last few months. Here we are not legally allowed to purchase anything of higher concentration that 12%.

What I see on the label often is as below:

HYDROGEN PEROXIDE 11.99% Food Grade

Ingredients: Hydrogen Peroxide 35% Food Grade: <11.99% w/v, Distilled Water: <88.01% w/v

I assume this is 35% that has been diluted down to 11.9% but what confuses me is why they even mention the 35%. Also it makes me query if it is even 11.9% total or 11.9% of 35% mixed with water. So 11.9/100 * 35% = 4.165% total?

Do you think this is probably confusing labelling or sharp practice to sell lower concentration 4.165% as 11.9%? If this was the case though the top line of the label would be false representation.
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Chemgineer
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[*] posted on 24-6-2023 at 08:42


I should add, it must be fairly high concentration as it has pressurised the sealed plastic bottle it comes in dishing out the bottom.
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[*] posted on 24-6-2023 at 09:45


Titrate it.



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Chemgineer
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[*] posted on 24-6-2023 at 12:27


Quote: Originally posted by Texium  
Titrate it.


I did a really rough titration with stoichiometric quantities assuming 12%. I only got about half of my potassium permanganate in before it stopped going clear.

I am assuming it is in fact around ~5-6%

So I do think they have diluted 35% and added water until this is at 11.98% thus not really 11.98% volume of hydrogen peroxide! Quite disappointing but the label is kind of accurate.
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[*] posted on 24-6-2023 at 20:55


Quote: Originally posted by Chemgineer  
I assume this is 35% that has been diluted down to 11.9% but what confuses me is why they even mention the 35%.

Yes, this is a fairly common practice. there's no (non-mystical) reason to specify the original concentration, but if I had to guess I'd say it originates from homeopathic dilution.




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Tsjerk
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[*] posted on 25-6-2023 at 01:01


Now the question is how pure was your permanganate? You could titrate that against sodium oxalate, Nurdrage just made a video about how and why on YouTube if you're interested.
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[*] posted on 25-6-2023 at 01:11


Quote: Originally posted by Tsjerk  
Now the question is how pure was your permanganate? You could titrate that against sodium oxalate, Nurdrage just made a video about how and why on YouTube if you're interested.

now the question is how pure will your sodium oxalate be




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Tsjerk
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[*] posted on 25-6-2023 at 03:14


Witty, but misplaced. Sodium oxalate can be reliably purified to an extent where the uncertainty becomes lower than other contributing factors. Potassium permanganate however is often impure and there is no way to purify it such that you can reliably use it in titration.

5-6% H202 titrated against permanganate of unknown purity is well within range of actually being 4,165%. That is why I suggested to titrate the permanganate.

[Edited on 25-6-2023 by Tsjerk]
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Lionel Spanner
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[*] posted on 25-6-2023 at 10:39


Quote: Originally posted by Chemgineer  
I should add, it must be fairly high concentration as it has pressurised the sealed plastic bottle it comes in dishing out the bottom.

That, or it's not adequately stabilised.




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[*] posted on 25-6-2023 at 15:59


I'm wondering, is sodium percarbonate a useful alternative to hydrogen peroxide or does the sodium cause too many problems?
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[*] posted on 28-6-2023 at 03:25


Quote: Originally posted by Chemgineer  
I'm wondering, is sodium percarbonate a useful alternative to hydrogen peroxide or does the sodium cause too many problems?
It’s just an adduct of sodium carbonate and hydrogen peroxide. whether or not the sodium carbonate presents a problem depends on what you’re doing



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