Question

Say you have a question asking to rank the oxidizing strength of several different metals.

When you look at the reduction table to determine the strength, there are metals with different oxidation states.

For example:
Fe3+ + 3e- => Fe ; Eo = -.04
Fe2+ + 2e- => Fe ; Eo = -.44

which one would you use to compare?

Answer 1

Use the one that is most likely to occur. In the case of the Fe metal, the USUAL oxidation is to the Fe^2+ and then to Fe3+ and not Fe to Fe^3+ in one step. That isn't always true but probably 90% or better. Most of the other metals do likewise.