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    Does anyone know the reaction mechanism or how the Iron(III) inhibits the reaction between sodium thiosulfate and hydrochloric acid?:confused: pretty please
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    probably because Fe(III) oxidises thiosulphate

    2Fe^{3+}  +  2S_2O_3^{2-} \rightarrow  2Fe^{2+}  +  S_4O_6^{2-}
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    thank you !!!!!!!!!
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    so does that mean it's a stronger oxidising agent than ermm is it hydrogen ions that oxidise S2O3 to S ??



    Na2S2O3 (aq) + 2HCl (aq) -> SO2(aq) + S(s) + H2O(l) + 2NaCl (aq)
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    H+ ions reduce things, not oxidize them.
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    true, so S gets reduced during reaction between thio and acid , so it is nothing to do with the oxidising strength of Fe (III), it's just the fact that it oxidises S2O3 so there is less of it to get reduced to solid sulfur ?
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    Not quite, the Fe(III) removes the thiosulphate so it can't react. Spot on. But it's not being reduced by the acid.

    (Wilsea05), H+ is an oxidising agent, rather than a reducing agent (as it removes electrons from things). The reaction of thiosulphate with HCl is an oxidation.
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    arghhh wish I was a chemistry genius like you are :P so let's get this straight: is Fe a stronger oxidising agent in the end and therefore removes thio before it can get oxidised by H+ to form solid sulfur?
    I can't find any theory on reaction mechanism for thiosulfate and acid so it's a bit confusing...
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    (Original post by Plato's Trousers)
    Not quite, the Fe(III) removes the thiosulphate so it can't react. Spot on. But it's not being reduced by the acid.

    (Wilsea05), H+ is an oxidising agent, rather than a reducing agent (as it removes electrons from things). The reaction of thiosulphate with HCl is an oxidation.
    The reaction of thiosulphate ions with acid is both oxidation and reduction - i.e. disproportionation.

    Na2S2O3 (aq) + 2HCl (aq) -> SO2(aq) + S(s) + H2O(l) + 2NaCl (aq)

    The hydrogen ions are a 'catalyst' in the redox process (not really, because they react with one of the products):

    S2O32- --> S + SO32-

    Which effectively get pulled to the RHS by the acid reacting with the sulphate (IV) ions formed in the disproportionation.

    SO32- + 2H+ --> H2O(l) + SO2
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    (Original post by b3mine)
    arghhh wish I was a chemistry genius like you are
    erm.. thanks, but I think charco has just demonstrated that I am not a chemistry genius

 
 
 
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