Free-energy change, ΔG∘, is related to cell potential, E∘, by the equation ΔG∘=−nFE∘
where n is the number of moles of electrons transferred and F=96,500C/(mol e−) is the Faraday constant. When E∘ is measured in volts, ΔG∘ must be in joules since 1 J=1 C⋅V.

Calculate the standard cell potential at 25 ∘C for the reaction

X(s)+2Y+(aq)→X2+(aq)+2Y(s)

where ΔH∘ = -691 kJ and ΔS∘ = -137 J/K .

Express your answer to three significant figures and include the appropriate units.