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In an electrochemical cell, the following half-reactions occur: Fe2+ -> Fe3+ + e- (E_cell for Fe3+/Fe2+ = 0.77 V) 2I- -> I2 + 2e- (E_cell for I2/I- = 0.54 V) The standard cell potential for the spontaneous overall reaction is x * 10⁻² V at 298 K. Find the nearest integer value of x.
- 23
- 54
- 77
- 31
Correct answer: 23
Solution
The spontaneous cell has I- oxidized at the anode and Fe3+ reduced at the cathode, giving E_cell = 0.77 - 0.54 = 0.23 V = 23 * 10⁻² V.
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