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Question:

For the following cell, Zn(s)|ZnSO4(aq)||CuSO4(aq)|Cu(s), when the concentration of Zn2+ is 10 times the concentration of Cu2+, the expression for ΔG (in J mol⁻¹) is: [F is Faraday constant; R is gas constant; T is temperature; E°(cell) = 1.1 V]

2.303RT+1.1F

−2F

2.303RT−2F

1.1F

Solution:

Zn + Cu²⁺ → Zn²⁺ + Cu
E⁰cell = 1.1V (given)
Ecell = E⁰cell − (2.303RT/nF)log[Zn²⁺]/[Cu²⁺]
Given that [Zn²⁺] = 10[Cu²⁺]
Ecell = 1.1 − (2.303RT/2F)log10
Ecell = 1.1 − (2.303RT/2F)
ΔG = −nFEcell
ΔG = −2F[1.1 − (2.303RT/2F)]
ΔG = −2.2F + 2.303RT