Question

How would you determine the standard electrode potential of the systemMg²⁺| Mg?

In the answer why SHE is only taken as cathode,why not anode?

Answer 1

In the cell Mg⁺⁺ | Mg reduction of ions occurs and hence the electrode behaves as cathode.
As the SHE can behave as both anode and cathode here it will behave as an anode.