6L.5b

[KDang_1D]

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

The solution says, "An inert electrode such as Pt is necessary when both oxidized and reduced species are in the same solution." What does this mean? The iodine and the cerium are in separate electrodes of the cell.

I understand that the two aqueous solutions of Ce3+ and Ce4+ would require a solid metal, but how would you know for I2(s)?

[Tyler Angtuaco 1G]

I think the statement about the necessity for an inert electrode refers to situations when the original species is in the same solution as its oxidized or reduced form. That is because I2 cannot be the anode since I- ions are already producing it in the process of oxidation.

[Lauren Tanaka 1A]

I think it means that the Pt is needed because there is no solid that can be either oxidized or reduced. Because of this Pt would need to be added to that side of the reaction.