Give the decreasing order of `E_((M^(3+))/(M^(2+))^(c-)` Value for the following:
(a). `Co(Z=27)`
(b). `Mn(Z=25)`
(c). `Fe(Z=26)`
(d). `Cr(Z=24)`

Explanation

`E_((M^(3+))/(M^(2+))^(c-)` values of the above element are: (table of 6.5)
(a). `E_((Co^(3+))/(Co^(2+))^(c-))=+1.97V`
(b). `E_((Mn^(3+))/(Mn^(2+))^(c-))=+1.57V`
(c). `E_((Fe^(3+))/(Fe^(2+))^(c-))=+0.77V`
(d). `E_((Cr^(3+))/(Cr^(2+))^(c-))=-0.41V`
So, the decreasing order of `E_((M^(3+))/(M^(2+))` value are `(a)gt(b)gt(c)gt(d)`