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Given,{:(E(Fe^(3+) //Fe)^o + 3e Cr E^o ...

Given,`{:(E_(Fe^(3+) //Fe)^o + 3e Cr E^o =- 0.036 V),(E_(Fe^(3+) //Fe)^o =- 0.439 V):}`
The value of standard electrode ptoential for the charge,

A

`0.770V`

B

`-0.27V`

C

`-0.072V`

D

`0.385V`

Text Solution

Verified by Experts

The correct Answer is:
A
`Fe^(3+) +3e rarr Fe` ...(1)
`E^(@) = 0.036V`
`:. DeltaG_(1)^(@) = nFE^(@)`
`=- 3 xx F(-0.036V)`
`= 0.108F`
Also, `Fe^(2+) +2e rarr Fe` ..(2)
`E^(@) =- 0.439V`
`:. DeltaG_(2)^(@) = nFE^(@)`
`=- 2 xx F(0.439)`
`=08.78 F`
For `Fe^(3+) (aq) +e^(-) rarr Fe^(2+) (aq)` ..(3)
`:.` Assume `E^(@) = xV`
eq.(1)-eq.(2) produces eq.(3)
`:. DeltaG^(@) = DeltaG_(1)^(@) - DeltaG_(2)^(@)`
`-1 xx F xx x = 0.108 F - 0.878F`
`- x =- 0.77`
`x = 0.77V`
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