Chemgineer
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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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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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Texium
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Titrate it.
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Texium
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Thread Moved
24-6-2023 at 09:45 |
Chemgineer
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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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SnailsAttack
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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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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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SnailsAttack
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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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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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| 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.
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That, or it's not adequately stabilised.
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Chemgineer
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I'm wondering, is sodium percarbonate a useful alternative to hydrogen peroxide or does the sodium cause too many problems?
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SnailsAttack
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| 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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