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Estimate the minimum potential difference required to reduce Al_(2)O_(3)at 500^(@) C. The free energy change for the decomposition reaction : 2/3Al_(2)O_(3) to 4/3 Al + O_(2) is DeltaG = 960 kJ 1 F = 96500 C mol^(-1). |
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Answer» Solution :The following data is provided `DeltaG^(@) = +960 kJ = 960 xx 10^(3) J, 1F = 96500 C mol^(-1)` The reduction equation may be written as: `4/3 Al^(3+) + 4e^(-) to 4/3 Al`. Thus, n=4. Use the following RELATION to calculate potential difference. `DeltaG^(@) = -nFE^(@)` `=-960 xx 10^(3) J =-4 xx 96500 C mol^(-1) xx E^(@)` volt or `E^(@) = (960 xx 10^(3) J)/(4 xx 96500 C mol^(-1)"volt") = +2.48 V` |
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