The standard potential of the cell (E°cell ) for the given reaction is calculated as: E°cell =E°cathode −E°anode E°Mg+2|Mg−E°Sn+2|Sn Apply Nernst equation, Ecell=(E°Mg+2|Mg−E°Sn+2|Sn)−
0.0591
n
log
Mg+2
Sn+2
Now, substitute all the values. Ecell =(−0.14−(−2.34))−