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I realise there are many questions and answers on this topic, but none has answered my question.

Why is the anode in a Galvanic cell negative? It makes more sense if it were positive because it is the side where electrons, having a negative charge, leave, and when electrons leave, it leaves behind a positive charge. Meanwhile on the other side, at the cathode side, incoming electrons should make the charge there increasingly negative as more and more electrons come over.

In the answers I have seen, people ask why is it defined this way/say that it is not a matter of definition. Please explain how it is not a mater of definition.

If you use money as an example, where electrons are debt, when debt moves away from you, you enter the black or become more positive. Given the same person and same situation, if you decided to define it differently, you could say that, since you had any debt to move to begin with, you are negative. Same situation, different definition.

Similarly in diagrams comparing galvanic and electrolytic cells, electrons move away from the anode to the cathode in the electrolytic cell, making the anode positive. This makes perfect sense according to my first reasoning. However, in a galvanic cell, even though electrons still move from the anode to the cathode, it is defined as negative. One answer I saw states that,

"the charge on the physical electrode does not change... simply, the actual chemical reaction at both electrodes is reversed so what was oxidation is now reduction and what was reduction is now oxidation, hence the labels anode and cathode are changed, even though the sign is not changed." (you can see this answer here)

This further confirms to me that positive and negative are merely definitions, the labels (man-bestowed name) are changed even though the signs (an intrinsic value that is determined by the movement of electrons) are not. Where is the logic behind calling the anode negative?

I have many questions
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    It's a definition. Blame Faraday if you want, but a decision had to be made about what to call the negative end and what to call the positive end. – Todd Minehardt Feb 18 '22 at 02:20
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    And blame Ben Franklin for the conventional current flow from positive to negative, and the arrow placement in the diode symbol. – DrMoishe Pippik Feb 18 '22 at 02:27
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    @ToddMinehardt Thank you! I finally have some sort of answer because I've been trying to figure out the logic behind the naming and it's driving me nuts. – I have many questions Feb 18 '22 at 06:23
  • @Ihavemanyquestions Not the origin of terminology, but a mnemotechnic hint: There is always oxidation at anodes (Greek anabasis = journey ( of electrons along the wire) upwards ), reduction at cathodes ( katabasis - journey downwards). ( The terms have usage span since ancient Homer and Xenophon till current meteorology, like anabatic and katabatic air vertical convection.) – Poutnik Feb 18 '22 at 14:51
  • @Poutnik Thank you but like I already (hopefully) implied (forgot to mention explicitly), I already know that anodes is where oxidation occurs (electrons move away from it) and cathodes reduction (electrons go to it), no matter the cell type. My question is about why anodes are negative in a galvanic cell when electrons move away from the anode and logically this should make the anode more positive. For some bizarre reason my question has been shut down and downvoted even though no other answer specifically answers this part of my question. – I have many questions Feb 18 '22 at 15:19
  • Think longer about anode having only oxidation and it is clear why it is more positive at electrolytic mode and more negative at galvanic mode. – Poutnik Feb 18 '22 at 15:23
  • @Poutnik If anode only ever has oxidation and oxidation is loss of electrons, and losing electrons makes one less negative ie more positive, then should it not be always positive regardless of whether it is galvanic or electrolytic? – I have many questions Feb 19 '22 at 13:34
  • Think even longer. in context of electronics, without any electrochemistry. Imagine "black box " circuitry with electrons always leaving pin A and always coming to pin B. In the case 1, it is externally powered. In the case 2, it is active power source, powering other circuit. What is mutual relative polarity of pins A and B in cases 1 and 2? – Poutnik Feb 19 '22 at 15:02
  • Or, look at it from point of view of work done. For the electrode with higher potential, when the work is done on the cell or on the external circuit, the direction of the current must be the opposite. Therefore for the same direction, relative potentials must be switched. – Poutnik Feb 19 '22 at 15:28

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It’s not the + and - which decides anode & cathode. Rather it’s the type of reaction that’s happening i.e. always oxidation occurs at anode & reduction occurs at cathode in cells ( galvanic and more) as well as electrolysis ( such as electrolysis of water)

Take an illustration:

  1. In the galvanic cell, at anode(-), Zn oxidises to Zn2+ And at cathode(+), Cu2+ reduces to Cu
  2. In electrolysis of water, at anode(+) OH(-) oxidises to O2 & at cathode(-), H+ reduces to H2
Shasankbt
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