Question

The standard electrode potential for the half cell reactions are
`Zn^(2+)+2e^(-)rarrZn ,E^(@)=-0.76V`
`Fe^(2+)+2e^(-)rarrFe,E^(@)=-0.44V`
The EMF of the cell reaction
`Fe^(2+)+ZnrarrZn^(++)+Fe` is
A. `-0.32V`
B. `-1.20V`
C. `+1.20V`
D. `+0.32V`

Answer 1

Correct Answer - D
`Fe^(2+)+ZnrarrZn^(2+)+Fe`
`ZnrarrZn^(2+)+2e^(-)`
`ZnrarrZn^(2+)+2e^(-)`
`Fe^(2+)+2e^(-)rarrFe`
`Zn|Zn^(2+)||Fe^(2+)|Fe`
`EMF^(@)=E_(Fe^(2+)//Fe)^(@)-E_(Zn^(2+)//Zn)^(@)`
`=-0.44-(-0.76)`
`=0.76-0.44=+0.32V`