I'm no expert nor scholar, but from what I am reading in all of these explanations, and what I notice from the illustration, it becomes obvious.at least to me.which I feel may clarify the polarity change between the Galvanic cell and electrolytic cell for this user.Īs established and understood, the source of electrons and transfer of ions flows from the negative pole, (Anode) and is received by the positive pole (Cathode) (intentionally using most basic terms) the anode is negative here because the the flow originates FROM the electrolyte, into the light bulb, for which, if the terminals of the bulb were labeled, they would match the electrolyte in the other cell as it is the force coming from the bulb pushing the flow to the cell's cathode, and the cell's cathode is pulling from the bulb. It stays the same, unaltered so that everytime a floodgate gets opened the water from the barrier lake will drop the same distance. And since the river is such a vast entity (lots of water) and usually flows into an ocean, the little "water" that is added to it doesn't change the river much. But the electrons don't stay in the electrode, so to speak, they are carried away by the river. At the negative electrode where you have produced a high electron potential via an external voltage source electrons are "pushed out" of the electrode, thereby reducing the oxidized species $\ce$ molecule. In an electrolytic cell, you apply an external potential to enforce the reaction to go in the opposite direction. Thus the anode is negative.Īt the cathode, on the other hand, you have the reduction reaction which consumes electrons (leaving behind positive (metal) ions at the electrode) and thus leads to a build-up of positive charge in the course of the reaction until electrochemical equilibrium is reached. Since at the anode you have the oxidation reaction which produces electrons you get a build-up of negative charge in the course of the reaction until electrochemical equilibrium is reached. Now, in a galvanic cell the reaction proceeds without an external potential helping it along. That's how cathode and anode are defined. Takes place while the cathode is the electrode where the reduction reaction The anode is the electrode where the oxidation reaction
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