What Determines the Spontaneity of Oxidation and Reduction Reactions?

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SUMMARY

The spontaneity of oxidation and reduction reactions is determined by the cell potential (E) and Gibbs free energy change (ΔG). For spontaneous reduction, Ecell must be positive, resulting in a negative ΔG, indicating that the cell performs work. Conversely, spontaneous oxidation occurs when E is negative, leading to a positive ΔG, which means the reaction requires external work to proceed. Thus, the relationship between E and ΔG is crucial for understanding the spontaneity of these electrochemical reactions.

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What is the different between spontaneous reduction and spontaneous oxidation? For spontaneous reduction you need to have Ecell to be (+), then what about spontaneous oxidation?

Thanks.
 
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The work done on the cell / by the cell is given as,
ΔG = -nFE
Where nF is used to determined the total charge passed into / out of the cell and E is the cell potential.
If E is positive, ΔG is negative.
If E is negative, ΔG is positive.

The reaction is spontaneous (the cell does work) when ΔG is negative (E is positive).
The reaction needs to be driven by an outside source (work done on the cell) when ΔG is positive (E is negative).
 

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