Multiple Choice
Using standard reduction potentials, calculate the standard emf for the following reaction: Co(s) + 2Co³⁺(aq) → 3Co²⁺(aq). What is the standard emf of this reaction?
20. Electrochemistry
Standard Reduction Potentials
Multiple Choice
What is the value (in V) of E°cell for the following reaction? Zn2+ (aq) + Pb (s) ⇌ Zn (s) + Pb2+ (aq)
A
-0.25 V
B
0.25 V
C
-0.63 V
D
0.63 V
Verified step by step guidance1
Identify the half-reactions involved in the overall cell reaction. For the given reaction, the half-reactions are: Zn²⁺ + 2e⁻ → Zn and Pb → Pb²⁺ + 2e⁻.
Determine the standard reduction potentials (E°) for each half-reaction from a standard reduction potential table. Typically, Zn²⁺ + 2e⁻ → Zn has a standard reduction potential of -0.76 V, and Pb²⁺ + 2e⁻ → Pb has a standard reduction potential of -0.13 V.
Calculate the standard cell potential (E°cell) using the formula: E°cell = E°cathode - E°anode. Here, the cathode is the reduction of Zn²⁺ to Zn, and the anode is the oxidation of Pb to Pb²⁺.
Substitute the values into the formula: E°cell = (-0.76 V) - (-0.13 V).
Simplify the expression to find the standard cell potential, ensuring the correct sign and value are determined.
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