A cell is to be constructed to show a redox change `:`
`Cr+2Cr^(3+)hArr3Cr^(2+)`. The number of cells with different `E^(c-)` an `n` but same value of `DeltaG^(c-)` can be made `(` Given `E^(c-)._(Cr^(3+)|Cr^(2+))=-0.40V,E^(c-)._(Cr^(3+)|Cr)=-0.74V,` adn `E^(c-)._(Cr^(2+)|Cr)=-0.91V)`

Answer

c

Explanation

`Cr|Cr^(3+)||Cr^(3+),Cr^(2+)|Pt(I),`
`Cr|Cr^(2+)||Cr^(3+)|Cr(II),`
`Cr|Cr^(2+)||Cr^(3+),Cr^(2+)|Pt(III,`
`(I) Crrarr Cr^(3+)+3e^(-),E^(c-)=+0.74V`
`3Cr^(3+)+3e^(-) rarr 3Cr^(2+),E^(c-)=-0.40V`
`ulbar(Cr+2Cr^(3+)rarr 3Cr^(2+)(n=3))`
`E^(c-)=0.74-0.4=0.34V`
`DeltaG^(c-)=3xx0.34xxF`
`=1.02F`
`(II)` `3Crrarr3Cr^(2+)+6e^(-),E^(c-)=-0.91V`
`2Cr^(3+)+6e^(-) rarr 2Cr,E^(c-)=-0.74V`
`ulbar(Cr+2Cr^(3+)rarr 3Cr^(2+)(n=6))`
`E^(c-)=0.91-0.74=0.17V`
`DeltaG^(c-)=0.17xx6xxF`
`=1.02F`
`(III)` `Cr rarr Cr^(2+)+2e^(-), E^(c-)=0.91V`
`2Cr^(3+)+2e^(-) rarr 2Cr^(2+),E^(c-)=-0.40V`
`ulbar(Cr+2Cr^(3+) rarr 3Cr^(2+)(n=2))`
`E^(c-)=0.91-0.40=0.51V`
DeltaG^(c-)=2xx0.51xxF`
`=1.02F`