How would you determine the standard electrode potential of the system `Mg^(2+) | Mg` ?

Explanation

* The standard electrode potential of `Mg^(2+)|Mg` can be measured with respect to the standard hydrogen electrode, represented by `Pt_((S)),H_(2(g))(1atm)|H_((aq))^(+)(1M)`.
* A cell, consisting of `Mg|MgSO_(4(aq))1M` as the anode and the standard hydrogen electrode as the cathode is set up.
`Mg|Mg_((aq))^(2+)(1M)||H_((aq))^(+)(1M)|H_(2(g))(1" bar")|Pt_((S))`
* Then, the emf of the cell is measured and this measured emf is the standard hydrogen electrode as the cathode is set up.
`Mg|Mg_((aq))^(2+)(1M)||H_((aq))^(+)(1M)|H_(2(g))(1" bar")|Pt_((S))`
* Then, the emf of the cell is measured and this measured emf is the standard electrode potential of the magnesium electrode.
`E^(Theta)=E_(R)^(Theta)-E_(L)^(Theta)`
* Here, `E^(Theta)` for the standard hydrogen electrode is zero.
Therefore, `E^(Theta)=0-E_(L=E_(L)^(Theta))^(Theta)`