Question

The Gibbs energy for the decomposition of `Al_(2)O_(3)` at `500^(@)C` is as follow :
`(2)/(3)Al_(2)O_(3) rarr (4)/(3)Al+O_(2), Delta_(r)G= +960 kJ mol^(-1)`
The potential difference needed for the electrolytic reduction of aluminium oxide `(Al_(2)O_(3))` at `500^(@)C` is
A. 3.0 V
B. 2.5 V
C. 5.0 V
D. 4.5 V

Answer 1

Correct Answer - B
`DeltaG^(@)=-nFE^(@)`
`960xx100=-4xx96500xxE^(@)`
`E^(@)=-2.48V`
So difference = 2.5 V