You do it this way. You're right; the oxidizing agent is reduced and the reducting agent is is oxidized. Oxidation is the loss of electrons and reduction is the gain of electrons. You have two problems so let's separate them.
Here are the two in the problem that can be reduced.
Ni^2+ + 2e ==> Ni Eo = ?
2H^+ + 2e ==> H2 Eo =
Look up those Eo values in the Ered tables. The one with the larger positive Eo value is the most easily reduced (which makes it the stronger oxidizing agent).
Then do the same with the reducing agents. Reducing agents are oxidized and oxidation is the loss of electrons so I'll write these as oxidations.
Al ==> Al^3+ + 3e Eo = ?
2I^- ==> I2 + 2e Eo = ?
You can't look up these equations in the Ered table BUT you can look up the reverse; i.e.,for the Al one you will find Al^3+ + 3e ==> Al. You will find that about -2.8 volts or so (I don't remember the exact number), then turn that equation around to what I have above (written as an oxidation) and change the sign to +2.8 or so. So the I^- the same way. The more positive Eox value will be the stronger reducing agent. Some profs don't like all this switching around. Your teacher may have a different way of doing this.
Now let me complain about the problem I don't know how you are to determine the BEST oxidizing agent or the BEST reducing agen. You can determine the strongest of each as I've outlined above but the BEST one depends upon what your trying to oxidize or reduce. Hope this helps.
Choose and best oxidizing agent and the best reducing agent: Ni2+, Al, H+, and I- ???
I'm so confused, please help!
I know the oxidizing agent is being reduced and the reducing agent is getting oxidized. But how do I use the standard reduction potential table? I can't find the right ones??
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