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Homework Help: Trying to Convert an Equation into an Ionic Equation

  1. Feb 17, 2015 #1
    1. The problem statement, all variables and given/known data

    PbSO4(aq) >>> Pb(s) + PbO2(aq) + S042-(aq)

    2. Relevant equations

    3. The attempt at a solution

    PbSO4(aq) must be Pb2+(aq) SO42-

    But PbO2(aq) seems to have to be Pb4+(aq) + 2O-(aq)

    How can Pb go from Pb2+(aq) to Pb4+(aq); doesn't it have to keep the same charge?
  2. jcsd
  3. Feb 17, 2015 #2


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    Staff: Mentor

    Both PbSO4 and PbO2 are solids.

    Note that there is no way to balance the equation as written - charge is only on one side.
  4. Feb 17, 2015 #3
    I'm sorry. I just noticed in brackets it says that they are soluble because they are in an acid solution.
  5. Feb 17, 2015 #4


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    Staff: Mentor

    Then the box is simply not true - please read about how the lead battery works. Its construction is based on the fact both these substances are solids immersed in the concentrated sulfuric acid.
  6. Feb 17, 2015 #5
    Thanks for the reassurance, it must be another mistake in my textbook.
  7. Feb 17, 2015 #6


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    Homework Helper
    Gold Member

    When you say it has to keep the same charge, no it does not - you also have Pb metal in there which has another charge (0). In fact not having the same charge is of the essence in oxidation of metals isn't it? and in the lead-acid battery you do have three levels of lead oxidation involved.
    It might help to try the formal non-ionic equation first, but you can't do it with what you've got in yours - you also need H2O.
    Then try to get the ionic one. Include H+. You are also allowed to use HSO4-. Spend a little time to try and get it, because if you do that first and then look it up it might click whereas if you only look it up you will say yes yes and forget it by next time. It is quite tricky.

    There is an account of this quite important application in links here: https://www.physicsforums.com/threa...ipitation-of-unknown-ion.790077/#post-4980286
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