Cell Diagrams

[Dustin Shin 2I]

Can someone explain to me why another element is needed to be put into the cell diagram even when its not in the chemical equations given? Also how would one even go about to choosing that one particular element?

[mbaker4E]

If you are referring to Pt(s) or C(graphite), those elements are added to the cell diagram if there is no solid present in the original equation. This is because if you refer to the visual representation of the cell diagram, the anode and cathode require a solid metal to transfer electrons from one side to the other. If the anode or cathode are not solid but rather aqueous or gaseous, Pt(s) and C(graphite) act as conductors for the electrons, but since they are inert substances they will not transfer electrons themselves.

[Aurbal Popal]

To answer the second part, I do not think it matters, but so far I have seen Pt being used more than C.

[Mya Majewski 1L]

A lot of times Ag(s) and Ni(s) will be used as electrodes too.