What will be standard cell potential of galvanic cell with the following reaction?
`2Cr_((s)) + 3Cd_((aq))^(2+) to 2Cr_((aq))^(3+) + 3Cd_((s))`
[Given: `E_(Cr^(3+)//Cr)^@`=-0.74 V and `E_(Cd^(2+)//Cd)^@`=-0.40 V]

Explanation

`E_(cell)^(ɵ)=E_(Cd^(2+)//Cd)^(@)-E_(Cr^(3-)//Cr)^(@)`
`=-0.40-(-0.74)`
`=-0.40+0.74=+0.34V`
the half cell reaction are
`2Cr(s)to2Cr^(3+)+6e^(-)`
`underline(3Cd^(2+)+6e^(-)to3Cd(s))`
`underline(2Cr(s)+3Cd^(2+)to2Cr^(3+)+3Cd(s))`
`therefore` No. of electrons `n=6`
`triangle_(r)G^(ɵ)=nFE^(ɵ)`
`=-6xx96500xx0.34`
`=-196.86kJmol^(-1)`