[Araconan]

So I'm currently studying Galvanic Cells, and according to my textbook, a galvanic cell is made by placing the reactants of the two half reactions into separate solutions connected by a wire, and a salt bridge. However, what I'm confused about, is how does each individual half reaction even occur?

For example, for the reaction 8H⁺ + MnO₄^- + 5Fe²⁺  Mn²⁺ + 5Fe³⁺ + 4H₂O, one of the half reactions would be Fe²⁺  Fe³⁺ + e^-.  This half reaction occurs because the MnO₄^- oxidises the iron, when the two collide. So if the MnO₄^- is kept separately from the iron, how can the half reaction occur (Where iron is oxidised) , since there's no oxidising agent?

Thanks in advance!

[Borek]

You are closing the circuit with a wire and a salt bridge, don't you?

[Arkcon]

We've been discussing these concepts recently in this thread here: http://www.chemicalforums.com/index.php?topic=61381.msg219077#msg219077