vibbzlab
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Chemistry gone wrong: peroxide, pH, peculiarities
I was working with making a video on thiosulfate
I dissolved some thiosulfate and found that the solution is acidic and I added hydrogen peroxide to it and the solution turned basic.
This should be the other way around right.
For me the universal indicator turned from red to greenish blue on adding hydrogen peroxide.
Any explanation to why that occured?
[edit by mod]
Clarified the title.
[Edited on 4-12-2019 by j_sum1]
Amateur chemist. Doctor by profession
Have a small cute home chemistry lab.
Please do check out my lab in YouTube link below
This is my YouTube channel |
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hodges
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I tested some medical (3%) hydrogen peroxide from the drug store and it is acidic - pH around 5. This is likely due to additives that help prevent
decomposition.
Intuitively, I would expect sodium thiosulfate to be slightly basic, since its constituents are a strong base and a (presumably) weaker acid.
However, when I tried adding a couple sodium thiosulfate crystals to water, the pH went up only very slightly, probably within the margin of error of
the reading. So it is probably very close to neutral. I don't see any reason to expect it would be acidic.
Not sure why you are seeing the opposite, although with such weakly acidic and basic solutions its possible that even a small amount of impurity would
have a rather large effect on the pH.
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vibbzlab
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I used the medical peroxide 3% one. So that's it. Thanks
Amateur chemist. Doctor by profession
Have a small cute home chemistry lab.
Please do check out my lab in YouTube link below
This is my YouTube channel |
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UC235
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The dyes in most pH indicators are sensitive to redox and can turn unpredictable colors in the presence of reducing agents (thiosulfate) or oxidizing
agents (hydrogen peroxide).
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fusso
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Title too vague and clickbaity. It should mention what you're actually doing. Change to a clearer one.
[Edited on 191203 by fusso]
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Tsjerk
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pka H2O2 = 11,7
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arkoma
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Aga started a thread on this same topic ages ago. Could we get a merge Mod's?
"We believe the knowledge and cultural heritage of mankind should be accessible to all people around the world, regardless of their wealth, social
status, nationality, citizenship, etc" z-lib
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j_sum1
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Considered it but this is quite a different kind of thread.
I will edit the title for clarity.
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