CHEMISTRY COMMUNITY

Why is it that the anode reaction is always reversed when determining the cell potential?

The standard cell potentials are written so that each compound is gaining electrons (aka cathode reaction) so if we want the equation where electrons are actually being lost, you have to reverse that standard cell potential value.

to get the real cell potential, we need to reverse the anode reduction reaction to make it an oxidation reaction.

Because all cell potentials are given in the reduction form and since the anode is being oxidized you switch the equation around so it represents that. Then when. calculated Ecell you can either do Ecathode-Eanode. or Ereduction+Eoxidation but you have to reverse the sign of the oxidation one

Because we need to show that it is being oxidized, so we flip it

Since all the cell potentials are given for reduction reactions, we have to flip the equation and the cell potential to get it for cell potential for the oxidation reaction, for the anode.

The values in the table are always standard reduction potentials, so since the anode is being oxidized and not reduced, the sign gets flipped.

The anode reaction is always reversed because usually when you look at the table, you get the reduction reaction the standard reduction potential. Since the anode is where oxidation occurs, you want the oxidation reaction. Therefore you would flip the reduction reaction to get the oxidation reaction, which means you would also make flip the sign of the standard reduction potential to get the standard oxidation potential.

If they are always given as recutions, How do you know which to flip to an oxidizer?

ursulavictorino1K wrote:If they are always given as recutions, How do you know which to flip to an oxidizer?

If they give you the cell potentials of each reaction, the reaction with the lower cell potential is the one that is oxidized so it will be flipped

the anode is being oxidized so you must flip the equation since all cell potentials are given in the reduction form