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Homework Help: Balancing using half reaction method

  1. Oct 31, 2008 #1


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    1. The problem statement, all variables and given/known data

    The redox reaction below occurs in basic solution. Balance it with the smallest whole number coefficients and determine the coefficient for OH-.

    H2CO(g) + Ag+(aq) ---> HCOOH(aq) + Ag(s).

    2. Relevant equations

    3. The attempt at a solution

    I got the oxidation numbers and found that Ag is reduced and the H2CO is oxidized, but I cant balance the half reactions, this is what I came up with:

    Ag+ + 1e- ---> Ag

    H2CO + H2O ---> 2HCOOH + 1e- + H2O
    Any help?
  2. jcsd
  3. Oct 31, 2008 #2


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    sorri i think i got it, can someone check?:

    2OH- + H2CO ---> 2HCOOH + 1e- + H2O

    so the coefficient for OH- is 2?
  4. Nov 1, 2008 #3


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    Staff: Mentor

    Charge is not balanced, carbon is not balanced, oxygen is not balanced... haven't checked hydrogen.
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