[chrisbb]

Hi!

I have a question about the anode and cathode. Right, this is what I know.

- The andoe = where oxidation occurs
- The cathode = where reduction occurs.
- E_cell = E_cathode - E_anode


When you have the standard potentials (say from the back of your book), a lot of the references I've see are all written in the forms of reduction equations.

For example: (just making this up)
Cu⁺²(aq)  +  2e-  Cu (s)   V = +0.95
Pb⁺²(aq)  +  2e-  Pb (s)    V = -0.36

Here is my question:
How do you identify which one is the anode and the cathode, by just looking at the standard potentials?
If both reactions are written as reduction, I'm find it hard to distinguish between the two.

Thanks,
Chris

[Matias Ekstrand]

Hi Chris,

The reaction with the most negative standard potential will be reversed. In your made up example, this would mean you have to reverse the reaction with Pb to oxidize it. This makes it the anode in your galvanic cell.

Just ask if anything is unclear.

[chrisbb]

thank you so much!
this really helps. Now I don't think I can mess these questions up