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Homework Help: Oxidation or Reduction

  1. Oct 3, 2008 #1
    1. The problem statement, all variables and given/known data

    Is this oxidation or reduction: (NO3)- ---> NO (this is a half reaction I took from the full equation)

    2. Relevant equations

    Not necessary

    3. The attempt at a solution

    At first, I got the oxidation states of each of the atoms

    For (NO3)- N has an oxidation state of 5+ and O has an oxidation state of 6-.

    for NO N has an oxidation state of 2+ and O has an oxidation state of 2-.

    and then I look at the charge of the whole compound.

    It goes from - to 0.

    therefore, i concluded that this is a oxidation equation.

    but it is actually a reduction equation

    Did I overlook something?
  2. jcsd
  3. Oct 3, 2008 #2


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    Homework Helper
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    Gold Member

    That is a reduction. Look at it this way:

    NO3 supscr -1 gives (-2)*3 charge from the oxygens. The charge on the Nitrogen is what? x + (-2)*3 = -1 means x=+5.

    Now, what happened in the half reaction? What is the charge that the Nitrogen now carries? How many electrons were gained OR how many electrons were lost? If the Nitrogen had to gain electrons then the half reaction was a reduction. If the Nitrogen had to loose electrons then the half reaction was an oxidation.
  4. Oct 4, 2008 #3


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    Staff: Mentor

    So, what happened to nitrogen, did it ON went up or down?

    Note: while ON for N are OK, you can't write

    There were three O atoms, each with ON -2. It is not the same, as your statement suggests each atom was -6.
    Last edited: Oct 4, 2008
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