The equilibrium constant, K, for a redox reaction is related to the standard potential, E∘, by the equation

lnK=nFE∘RT

where n is the number of moles of electrons transferred, F (the Faraday constant) is equal to 96,500 C/(mol e−) , R (the gas constant) is equal to 8.314 J/(mol⋅K) , and T is the Kelvin temperature.

Calculate the standard cell potential (E∘) for the reaction

X(s)+Y+(aq)→X+(aq)+Y(s)

if K = 1.89×10−3.

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