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Question:

Following reaction takes place in the cell: Zn(s) + Ag₂O(s) + H₂O(l) → Zn²⁺(aq) + 2Ag(s) + 2OH⁻(aq) Calculate ΔrG⁰ of the reaction. [Given: E⁰_(Zn²⁺/Zn) = -0.76V, E⁰_(Ag⁺/Ag) = 0.80V, 1F = 96,500 C mol⁻¹]

Solution:

E⁰cell = E⁰R - E⁰L = 0.8 - (-0.76) = 1.56V
In the given reaction, the no. of electrons transferred is 2, i.e., n=2
As we know that,
ΔG⁰ = -nFE⁰cell
→ΔG⁰ = -2 × 96500 × 1.56 = -300.8kJ
Hence the value of ΔG⁰ for the given reaction is -300.8kJ.