CHEMISTRY COMMUNITY

How do we know when we are supposed to add Pt(s) to a cell diagram?

I was confused about that. In the 6th edition for 14.13, the solutions manual didn't use platinum for the reaction with nickel and zinc but used it in part b for the reaction between I and Ce, and also between H and Cl.

We use platinum in the reaction when our half reactions have no conducting solids (such as iron and copper redox) because platinum can be used as an inert conductor, an electrode to transfer electrons.