Question

A galvanic (voltaic) cell consists of an electrode composed of magnesium in a 1.0 M magnesium ion solution and another electrode composed of gold in a 1.0 M gold(III) ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C. Standard reduction potentials can be found here.

Answer 1

Reaction taking place at anode Mg(s)   --------- > Mg^2+(aq) + 2e-                 Eo = -2.38 V

reaction taking place at cathode =   Au^3+(aq) + 3e-      ---- > Au                         Eo = +1.50 V

Formula to calculate the stadard cell potential is

Eo cell = Eo cathode - Eo anode

           = 1.50 V -(-2.38 V)

           = 3.88 V