An electrolytic refining cell for copper consists of an alloy with activity of copper ac_u = 0.8 as the anode, and pure copper as the cathode. What is the absolute value of the cell potential (in millivolts) at 25°C, given that copper is divalent? Faraday constant is 96500 C/mol and the universal gas constant is 8.314 J/(mol.K).

A. 2.9

B. 4.6

C. 6.8

D. 8.9

Answer: Option A