Which expression correctly gives Ecell according to the source?

Which expression correctly gives Ecell according to the source?

• A. Ecathode + Eanode
• B. Ereduction + Eoxidation
• C. Eoxidation + Ereduction
• D. Ecell - E°cell

Answer: (B)

Ecell comes from combining the two half-reactions in the directions they actually occur: reduction at the cathode and oxidation at the anode. Each half-reaction has an associated potential. If you take the reduction potential for the cathode and the oxidation potential for the anode and add them, you obtain the overall cell potential. This is equivalent to the usual expression Ecell = E°cathode − E°anode, because the oxidation potential of the anode is the negative of its reduction potential. So Ereduction + Eoxidation is the correct way to express the cell potential.

Ecell comes from combining the two half-reactions in the directions they actually occur: reduction at the cathode and oxidation at the anode. Each half-reaction has an associated potential. If you take the reduction potential for the cathode and the oxidation potential for the anode and add them, you obtain the overall cell potential. This is equivalent to the usual expression Ecell = E°cathode − E°anode, because the oxidation potential of the anode is the negative of its reduction potential. So Ereduction + Eoxidation is the correct way to express the cell potential.