CHEMISTRY COMMUNITY

Hiya,

When do you determine whether to separate elements by | or by commas? I'm having trouble figuring out why the answer book uses commas in some cases, or even includes some elements. In addition, while I understand why Pt is used, I'm not sure when to determine to use Pt as the electrode. A specific example is: HW question 17, part b.

MnO4 + 5Fe + 8H goes to Mn + 5Fe + 4H2O becomes
Pt | Fe || H, MnO4, Mn | Pt.

Cheers

I have written down in my notes that if you have a solid metal in reaction, then you should use it as the electrode. If not then use an inert conductor as the electrode (e.g. Pt) to transfer the e-. In this problem Fe and Mn are both in the solution so you would use Pt. The " | " I'm pretty sure is what separates the electrode and the atoms involved in the reaction. If there is more than one atom involved in the half reaction, you separate these by a comma. Also if one of the atoms involved in the half reaction is used as the electrode, then you don't have to repeat it after the " | ".

I hope this helps