When to use Platinum

[Charles Hood Disc 1C]

In a galvanic cell, when do you use an electrode? (As in an added on one, it seems to most commonly be platinum).

How do you decide which element to use as the extra electrode?

[Sarah Kiamanesh 1D]

Take this reaction, for example:
Cu(s)+2Fe3+(aq)→Cu2+(aq)+2Fe2+(aq)

The cell diagram becomes
Cu∣Cu2+∥Fe2+,Fe3+∣Pt

Since both Fe2+ and Fe3+ are in solution, a Pt electrode is used

[Becky Belisle 1A]

You add an inert electrode, such as Platinum, when the anode or cathode is lacking a metal in the solid state. For instance, when the substances in the cathode are both aqueous, Platinum could be added.

[Jordan Lo 2A]

Platinum electrodes are used because they aren't very reactive, so they won't be involved in the oxidation/reduction. We use them when we have two ions involved so that electrons can flow between the cells

[deepto_mizan1H]

Using an inert electrode (most often Pt) allows the half of the cell to facilitate reduction/oxidation when the solution is fully aqueous. Electrons will be transferrable on the surface of the electrode. If the electrode is involved in the half cell with the solution (solid copper and aqueous), then we have no need to use the Pt.

[Aria Soeprono 2F]

You need to have one conductive metal on each side of the galvanic cell. Therefore, if one side only has aqueous solutions (and therefore non-conductive), you have to add platinum as an electrode to that side.