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Reactions of Halogens with Metals

  1. Feb 23, 2012 #1
    To test the ability of Br2 and I2 to oxidize copper metal, the reactions take place between Br2water and I2 solution with copper:

    Cu (s) + Br2 (aq) -> Cu2+ (aq) + 2Br- (Aq)

    Cu(s) + I2 (methanol) -> Cu2+ (methanol) + 2I- (methanol).

    Write the net ionic equations describing the results of these two experiments.

    I believe that the Cu (s) should oxidize, and thus color change. Particularly with Br2 water (bromide water), so I recorded the net ionic equation as 2Cu (s) + Br2 (aq) -> 2CuBr(s)

    However, I'm unsure if this is correct or what to do with the second equation.

    Has anyone ever done these reactions or know them off hand? Is it possible that a precipiate could form between Cu2+ and I2?
  2. jcsd
  3. Feb 24, 2012 #2


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    Staff: Mentor

    Why not CuI?

    Actually I am sure about CuI, but I am not convinced you will get CuBr and not CuBr2.
  4. Feb 24, 2012 #3
    Well, CuI would have to be a solid. And I'm not convinced a solid was formed in this case. I suppose my main question is if the reaction between Cu and I2 results in a color change to Cu, would the product be a solid? CuI would have to be a solid to be written as such in the net ionic equation.

    The lab notes predict Br2 reduces to Br2-, hence my writing CuBr
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