Cell Diagrams

[mitalisharma2B]

When writing cell diagrams based on balanced equations how do we know when to add Pt(s) onto each end of the reaction?
For example, see 13b from chapter 14.

(b) Ce4+(aq) + I-(aq) --> I2(s) + Ce3+(aq)

the solutions say that the cell diagram is
Pt (s) | I-(aq) | I2(s) || Ce4+(aq) | Ce3+(aq) | Pt(s)

Thanks!

[PranithaPrasad]

If you have a metal, then you won't need an inert conductor like Platinum. But in cases like this, where you only have aqueous compounds and only nonmental solids, you would need platinum so that there would be a transfer of electrons. I hope this helps!

[mitalisharma2B]

Thank you!!