Past exam of the MPhil in micro- and nanotechnology enterprise course of the University of Cambridge / 2021 / Paper 1 / 6 / i

The species that oxidizes nickel is gold(III) ion, rather than metallic gold. The half-reactions areMultiplying the first by three and the second by two givesStandard electrode potentials are not multiplied by the balancing factors. Thus $E_{\mathrm{cell}}^{\circ }=1.50-(-0.25)=1.75\mathrm{V}$ and six moles of electrons are transferred per mole of this balanced reaction:The negative sign predicts a thermodynamically favorable galvanic replacement under standard conditions.