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Tsjerk
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Yes, so the salt and sulfuric acid together make Caro's acid. Without acid the salt is quite tame.
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Keras
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But the redox potential of the anion is unchanged.
Wikipedia says the redox potential of HSO₅⁻ + 2 H⁺ + 2 e⁻ → HSO₄⁻ + H₂O is +1.81 V
2 Br⁻ → Br₂ + 2 e⁻ E = -1.025 V
So: HSO₅⁻ + 2 H⁺ + 2 Br⁻ → HSO₄⁻ + H₂O + Br₂ has ∆E ~ 0.8 V
Ok, you need to use an acid to get the reaction going, but HCl should suffice.
[Edited on 5-8-2021 by Keras]
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RustyShackleford
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Quote: Originally posted by Keras  |
What's the purpose of the sulphuric acid here? Isn't oxone already oxidising enough to get the bromine out?
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in retrospect i believe it may be unnecessary, as i have heard from someone else that it works without any acid at all (atleast in the case of pure
persulfate). I added it because i calculated/designed the reaction using the normal mechanism w peroxide, which relies on HBr forming.
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RustyShackleford
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| Quote: Originally posted by Keras |
But the redox potential of the anion is unchanged.
Wikipedia says the redox potential of HSO₅⁻ + 2 H⁺ + 2 e⁻ → HSO₄⁻ + H₂O is +1.81 V
2 Br⁻ → Br₂ + 2 e⁻ E = -1.025 V
So: HSO₅⁻ + 2 H⁺ + 2 Br⁻ → HSO₄⁻ + H₂O + Br₂ has ∆E ~ 0.8 V
Ok, you need to use an acid to get the reaction going, but HCl should suffice.
[Edited on 5-8-2021 by Keras] |
HCl would be terrible in this case, as it would form chlorine gas and interhalogens. bisulfate would likely work though, for an alternative to
sulfuric.
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