Question

`E^@` values for the half cell reactions are given below :
`Cu^(2+) + e^(-) to Cu^(+) , E^@`=0.15 V
`Cu^(2+) + 2e^(-) to Cu, E^@`=0.34 V
What will be the `E^@` of the half-cell : `Cu^(+) + e^(-) to Cu` ?
A. `+0.49 V`
B. `+0.19 V`
C. `+0.53V`
D. `+0.30V`

Answer 1

Correct Answer - C
`{:(Cu^(2+)+e^(-) to Cu^(+) ,,E_(1)^(@)=0.15 V","DeltaG_1^@","n_1=1),(Cu^(2+)+2e^(-) to Cu , ,E_2^(@)=0.34 V","DeltaG_2^(@)","n_2=2),(Cu^(+)+e^(-) to Cu,,E_3^(@)=?"," DeltaG_3^(@)","n_3=1),(DeltaG_3^@ = DeltaG_2^@-DeltaG_1^@ rArr ,-n_3FE_3^@=-n_2FE_2^@+n_1FE_1^@):}`
`-E_3^@` = -2 x 0.34 + 1 x 0.15
`E_3^@`= 0.68 - 0.15 = +0.53 V