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November 01, 2025, 01:09:43 pm

Author Topic: Galvanic Cell confusion  (Read 901 times)  Share 

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Edward21

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Galvanic Cell confusion
« on: October 06, 2013, 09:50:32 pm »
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In a galvanic cell, the anode is - and the cathode +

Anions flow to the half-cell containing the anode, to replace negative charge that is being lost due to oxidation.
Cation flow to the half-cell containing the cathode, to replace positive charge that is being lost to due reduction.

If I have let's say SO42-, where would it have a net migration towards??? This exam says the positive cathode, which makes sense, negative to positive, but aren't anions supposed to flow to the half-cell containing the anode??? It's two conflicting things HELP  ???
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lzxnl

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Re: Galvanic Cell confusion
« Reply #1 on: October 06, 2013, 10:41:32 pm »
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I think it partially depends on where the sulfate ions are.

Anions in the salt bridge migrate towards the anode. That is necessary for the cell to form a closed circuit.

Where are these sulfate ions?
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Edward21

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Re: Galvanic Cell confusion
« Reply #2 on: October 06, 2013, 10:43:30 pm »
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I think it partially depends on where the sulfate ions are.

Anions in the salt bridge migrate towards the anode. That is necessary for the cell to form a closed circuit.

Where are these sulfate ions?
Lead-acid accumulator. It asks which ions will have a net movement towards the positive electrode, and I was torn between them being attracted to the positive cathode, or to restore electronegativity in the anode region  :-[
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lzxnl

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Re: Galvanic Cell confusion
« Reply #3 on: October 06, 2013, 11:09:15 pm »
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Lead-acid accumulator. It asks which ions will have a net movement towards the positive electrode, and I was torn between them being attracted to the positive cathode, or to restore electronegativity in the anode region  :-[

I would be careful of your last clause. "Electronegativity" is the ability of an atom to attract electrons. I think you mean electric charge. Just be careful; the examiners may not like your comment much.

I presume you're speaking of the discharging process.
In that case, electrons spontaneously flow from the negative anode to the positive cathode. I wouldn't expect the sulfate ions to be attracted to the cathode actually; negative charge is already flowing there, and if sulfate ions were attracted there, the cathode would have a charge imbalance, plus the circuit wouldn't be completed.
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English Language (50) Chemistry (50) Specialist Mathematics (49~54.9) Physics (49) UMEP Physics (96%) ATAR 99.95

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Edward21

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Re: Galvanic Cell confusion
« Reply #4 on: October 06, 2013, 11:38:17 pm »
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I would be careful of your last clause. "Electronegativity" is the ability of an atom to attract electrons. I think you mean electric charge. Just be careful; the examiners may not like your comment much.

I presume you're speaking of the discharging process.
In that case, electrons spontaneously flow from the negative anode to the positive cathode. I wouldn't expect the sulfate ions to be attracted to the cathode actually; negative charge is already flowing there, and if sulfate ions were attracted there, the cathode would have a charge imbalance, plus the circuit wouldn't be completed.
Sorry! Electroneutrality is a word I've seen mentioned in a textbook before, and I accidentally slipped in Electronegativity whoops! 1/2 Chem  :-[
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