Negative Standard Potential

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Elizabeth Bowen 1J
Posts: 53
Joined: Wed Nov 14, 2018 12:20 am

Negative Standard Potential

Postby Elizabeth Bowen 1J » Thu Mar 05, 2020 1:49 am

In the textbook, it says that a negative standard potential means that a redox couple is more strongly reducing (rather than oxidating), but I'm a bit confused because doesn't a negative standard potential just mean that delta G will be positive, so the reverse of whatever electrode reaction we're given will just be the spontaneous reaction? (because of the equation delta G=-nFE) or that the given reaction is nonspontaneous? Because it seems like the cathode would always have a positive standard potential, and the anode would always have a negative standard potential, but that doesn't really make sense because all the reactions in a Galvanic Cell (both 1/2 rxns) are supposed to be spontaneous, so would that mean that the standard potentials at the cathode and anode should both be positive because that's the only way to have a negative (spontaneous) delta G?

Ally Huang- 1F
Posts: 103
Joined: Thu Jul 25, 2019 12:16 am

Re: Negative Standard Potential

Postby Ally Huang- 1F » Thu Mar 05, 2020 11:31 am

In order to get a negative delta G, E° must be positive. In order to get a positive E° one of the standard potentials can still be negative, as long as the sum of the standard potentials is positive.

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