Adding an Electrode to a Cell Diagram?

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Adding an Electrode to a Cell Diagram?

Postby HoganFenster2E » Tue Feb 02, 2016 5:40 pm

For the Cell Diagram in the attached photo, why is Platinum only added to the Cathode and not the Anode? The original reaction was 2NO3- (aq) + 8H+ (aq) +6Hg(l) > 3Hg2 2+ (aq) + 2NO (g) + 4H2O (l)
Also when do we add an electrode like platinum to a cell diagram?

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Re: Adding an Electrode to a Cell Diagram?

Postby Chem_Mod » Tue Feb 02, 2016 11:19 pm

You typically add an electrode when you do not have one already in the reaction. In this case, Hg (l) has a standard potential and is not an ion so it is the electrode. On the other side, NO3 (aq) and NO(g) are not pure elements so there needs to be an electrode to measure the potential.

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