Multiple Choice
Calculate the standard cell potential for the electrochemical cell: Pb2+(aq) + Mn(s) → Pb(s) + Mn2+(aq). Given the standard reduction potentials: E°(Pb2+/Pb) = -0.13 V and E°(Mn2+/Mn) = -1.18 V.
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20. Electrochemistry
Cell Potential: Standard
Multiple Choice
Which equation is used to calculate the theoretical cell potential (E^ext{cell}) under standard conditions for a galvanic cell?
A
E^ext{cell} = E^ext{cathode} + E^ext{anode}
B
E^ext{cell} = E^ext{anode} - E^ext{cathode}
C
E^ext{cell} = E^ext{cathode} - E^ext{anode}
D
E^ext{cell} = E^ext{anode} imes E^ext{cathode}
Verified step by step guidance1
Understand that the theoretical cell potential, \(E^{\text{cell}}\), for a galvanic cell is calculated by combining the standard reduction potentials of the cathode and anode half-reactions.
Recall that the cathode is where reduction occurs and the anode is where oxidation occurs, and their potentials are given as standard reduction potentials, \(E^{\text{cathode}}\) and \(E^{\text{anode}}\) respectively.
The correct formula to find the cell potential is to subtract the anode potential from the cathode potential, because the anode potential must be reversed (oxidation) when calculating the overall cell potential.
Write the equation as \(E^{\text{cell}} = E^{\text{cathode}} - E^{\text{anode}}\), which gives the net voltage produced by the galvanic cell under standard conditions.
Note that adding or multiplying the potentials directly is incorrect because potentials are based on reduction half-reactions and must be combined by subtraction to reflect the oxidation at the anode.
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