Standard electrode potential for `Sn^(4+)//Sn^(2+)` couple is `0.15 V` and that for the `Cr^(3+)//Cr` couple is `-0.74 V`. These two couples in their standard state are connected to make a cell. The cell potential will be

Options

A. `+0.18V`
B. `+1.83V `
C. `+1.19V`
D. `+0.89V`

Answer

D

Explanation

`E_(Sn^(4+)//Sn^(2+))^(@)= +0.15V :E_(Cr^(3+)//Cr)^(@)=-0.74`
`therefore E_("cell")^(@)=E_(C)^(@)-E_(A)^(@)=0.15-(-0.74)=0.89V`.