Non-Redox Reaction Calculation of Cell Potential

[WordSword]

All reactions have some degree favorability at standard conditions, and therefore free-energy value. Yet, not every reaction is a reduction/oxidation reaction.

Is the relationship ∆G = -nFE valid for non redox reactions?

For example, if a reaction 2AB2 → A2B4 has a ∆G value for, say, 50 kJ/mol, can we solve for E even though this isn't a redox reaction? I know n is the number of electrons transferred per reaction, so if there's no electrons transferred, then ∆G = 0. But, if theres a ∆G value for this reaction how does this energy to voltage change equation valid? Maybe I'm confused and need general concept help. Any insight?

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[Cawolf]

∆G is calculated differently for different types of reactions. If it is not a redox reaction, then what type of reaction is it?

For example,

∆G = -RTln(ksp)

∆G = ∆H - ∆TS

The equation you posted is derived from the Nernst equation which shows the relationship between standard - state cell potential and the cell potential.

 

[WordSword]

If it is not a redox reaction, then what type of reaction is it?

This would be a composition reaction.

I'm still confused. I understand how the equations you listed describes the free-energy relationship, but the cell potential can also describe how to get free energy. If free-energy equals a value from using ∆G = ∆H -T∆S, then why can you not use that value in the cell-potential/free-energy relationship to calculate the cell-potential?