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

Explanation

A cell will be set up consisting of `Mg//MgSO_(4)(1M)` as one electrode and standard hydrogen electrode Pt, H, (1atm) `H^(+)//(1M)` as second electrode, measure the EMF of the cell and also note the direction of deflection in the voltmeter. The direction of deflection shows that `e^(-1)` s flow from mg electrode to hydrogen electrode, i.e., oxidation takes place on magnesium electrode and reductio on hydrogen electrode. Hence, the cell may be represetned as follows.
`Mg|Mg^(2+)(1M)||H^(+)(1M)|H_(2),(1atm),Pt`
`E_(Cell)^(@)=E_(H^(+)//(1)/(2)H_(2))^(@)-E_(Mg^(2+)//Mg)^(@)`
Put `E_(H^(+)//(1)/(2)H_(2))^(@)=0`
`thereforeE_(Mg^(2+)//Mg)^(@)=-E_(cell)^(@)`