Pt (s) [ENDORSED]

[Mona El Masri 1F]

Do we add Pt solid to reactions that contain a liquid as well, or only aqueous and gas?

[Ashley Zhu 1A]

you do not need to add Pt(s) to liquids in cases where you have Hg(l) and Hg ions, but I am not sure if there are any exceptions/other cases

[Sophia Ding 1B]

Why do you not need to add Pt(s) to liquids?

[Celine Hoh 2L]

I think we also add Pt when both species of the same kind are in the same solution, say Fe2+ and Fe3+

[Arta Kasaeian 2C]

We add Pt(s) to any side of the diagram (anode or cathode) that doesn't include a solid conductor within the reaction.

[Daisylookinland]

In the homework problem 6L5 part b in the 7th edition, one of the cell diagrams is Pt(s)|I^-(aq)|I2(s)||Ce^4+(aq), Ce^3+(aq)|Pt(s)

I don't really understand why the Pt is included here, can someone explain?

[Kyleigh Follis 2H]

Pt is included because in the cathode are two ion compounds in solution, so an inert electrode is needed.

[Nina Do 4L]

Hi,

You would add Pt(s) or C(graphite) if there is no solid acting as an anode or cathode. You still would need to add a solid (either platinum or carbon graphite) in the presence of an aqueous solution because that represents the aqueous solution that the anode/cathodes would be in. So in the absence of a solid, add Pt(s) or C(gr)

[Chem_Mod]

The above answers are correct! Great job, everyone.

As for the homework problem, many students get confused by the solid I₂. You need to remember that not all solids are conductors. You must have a metal for it to conduct, and I₂ is not a conducting metal. Therefore, you need to add Pt as an electrode.