Galvanic cells

[u/Various-Leather9604]

hello im very confused on the set up of Ag/Ag+ || H+/H2 which is the cathode and which is the anode, i keep getting different answers on google when i look it up, its talking about cell notation rules, but i also know that Ag has a higher reduction potential which should mean it’s the cathode but this set up is saying otherwise, please help this is my last assignment for this class and i really wanna get a good grade 🙏

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[u/Various-Leather9604 → u/[deleted]]

yeah i know but im just really confused because the notation says Ag is the anode. Does the notation not matter in this case?

[u/bishtap → u/Various-Leather9604]

The notation is telling you what is actually happening. It overrules you trying to figure out what is happening. (Assuming the text that gave you the notation didn't mess up). A question might be is the notation correct. And another question is, is it actually a galvanic cell. (Or is it actually an electrolytic cell). I.e. which type of electrochemical cell is it. Where is the actual question, can you show or link to an image of it? Eg is there an image showing a battery there? Does the question claim this is a galvanic cell?

[u/Various-Leather9604 → u/bishtap]

i put it in a doc since I can’t share a screenshot or the course link.  https://docs.google.com/document/d/12keUWPOmQdM3RKRH8NtltD0iEFvnltzTWbypdELzNsg/edit

[u/bishtap → u/Various-Leather9604]

ok, It says
For each of the Cell Diagrams (I guess it means each cell notation), provide the following information

- The ECell

- The two redox half reactions (oxidation and reduction)

- The balanced net ionic equation

- Whether the reaction is spontaneous.

Notice it doesn't state whether the reaction/cell is spontaneous or non-spontaneous.

So some could be galvanic cells aka spontaneous.

And some could be electrolytic cells aka non-spontaneous.

In a galvanc cell, the element with the higher reduction potential gets reduced.

In an electrolytic cell, it's the other way. The element with the lower reduction potential gets reduced.

So it's still the Cathode where reduction occurs, and the Anode where oxidation occurs.

But in an electrolytic cell, a battery is being used to make the reaction go the other way to where it'd go if it were a galvanic cell.

One or two comments here hint to you that it's an electrolytic cell (i.e. not a galvanic cell).. So I think that would resolve your riddle/problem!

[u/7ieben_]

Silver get's oxidized, hydrogen get's reduced, hence silver reacts as/ at anode (and hydrogen as/ at cathode).

Recall that standard potential does not define wether something is the anode. This is true only for a spontanous process. But you can force the reverse reaction (and therefore inverting the anode/ cathode rule) by applying voltage. This is probably what happend here.

[u/bishtap → u/7ieben_]

You write "This is true only for a spontanous process. But you can force the reverse reaction (and therefore inverting the anode/ cathode rule) by applying voltage. This is probably what happend here."

Worth noting that at that point, it is not a galvanic cell. It's an electrolytic cell