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Disproporationation of halogens with alkalis watch

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    Halogens disproportionate differently in hot and cold alkalis. For example, in a cold alkali, a bromate(I) ion could be made. In hot alkali, bromate(III) could be made.

    I'm wondering how do you know which ones are made. So far I think in hot alkali the ion tends to be more oxidised than in cold (i.e higher oxidation number).

    My book gives:
    Chlorate(I), bromate(I), bromate(III), iodate(V) and iodate (VII)

    I'm doing Edexcel unit 2 btw.
    Are those ions the only ones that can be made in this type of reaction? Can't you get iodate(III)?

    Also it said something about the ions may decompose to give more halide/halate ions? :\
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    The reactions you need to know for Edexcel Unit 2:
    (I will be using Iodine and Bromine as examples but they could be any general halogen)

    Cold Alkalis
    I2 + 2NaOH --> NaIO + NaI + H2O

    Hot Alkalis
    3Br2 + 6NaOH --> NaBrO3 + 5NaBr + 3H2O
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    (Original post by overclocked)
    The reactions you need to know for Edexcel Unit 2:
    (I will be using Iodine and Bromine as examples but they could be any general halogen)

    Cold Alkalis
    I2 + 2NaOH --> NaIO + NaI + H2O

    Hot Alkalis
    3Br2 + 6NaOH --> NaBrO3 + 5NaBr + 3H2O
    Thanks!
    For NaIO, what are the ions?
    Na+ and IO-? I think I saw OI- once... whats the difference?
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    (Original post by Phalange)
    Thanks!
    For NaIO, what are the ions?
    Na+ and IO-? I think I saw OI- once... whats the difference?
    Yes that's right and there is no difference.
 
 
 
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