A student builds a Cu concentration cell with two Cu electrodes immersed in 0.0010 M and 1.00 M Cu(NO3)2 with a salt bridge. At 25 C the measured cell potential is +0.088 V (left half-cell positive). E^o for the same metal in both half-cells is 0 V; the Nernst equation gives E_cell = -(0.0592/2) * log(Q).
Which electrode is the cathode?
- A
the Cu electrode in 0.0010 M Cu^2+
- Bcheck_circle
the Cu electrode in 1.00 M Cu^2+
- C
both function as cathodes simultaneously
- D
neither - the cell is at equilibrium
Explanation
Reduction of Cu^2+ -> Cu is favored where [Cu^2+] is greater. The cathode is the electrode in 1.00 M Cu^2+.