I was reading an online material then I came upon a cell notation for an electrolytic cell (I determined that it was an electrolytic cell because of the absence of a salt bridge). Usually, I will proceed on reading but then I realized, since cathode and anode is switched for an electrolytic cell, which side of the cell will be the cathode and the anode?

The example given was:

$$\ce{Ag | AgCl(s), Cl- (\pu{0.200 M}), Cd^2+ (\pu{0.00500 M}) | Cd}$$

  • $\begingroup$ This could be simply a Ag|AgCl electrode, a Cd electrode and a solution that is 0.200 M in chloride ion, 0.005 M in cadmium ion and, say, 0.190 M in sodium ions. All in one beaker, so no salt bridge. The context in what you were reading matters. $\endgroup$
    – Ed V
    Jul 30, 2019 at 12:51
  • $\begingroup$ So, is the Ag l AgCl side the anode? $\endgroup$ Jul 30, 2019 at 12:53
  • $\begingroup$ This is where the Nernst equation get used: you calculate the two reduction potentials and the most positive one is the spontaneous reduction. Then the other one is the oxidation side and it is conventionally on the left. $\endgroup$
    – Ed V
    Jul 30, 2019 at 12:57

1 Answer 1


A good mnemonic to remember which is the anode or the cathode is to remember that Right side represents Reduction in a cell diagram. This is fixed by those who invented cell notation.. Also, by definition, reduction occurs at the cathode. Whether it is a spontaneous cell or not, is another question.

Now as EdV said, calculate the cell potential as written i.e., consider cadmium half cell as the cathode, and the other silver electrode as the anode. If the Ecell=Ecathode-Eanode turns out to be positive, everything is fine, all that means that the cell, as written, is a spontaneous cell.

If Ecell is negative, then the cell is non-spontaneous.


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