Use the tabulated half-cell potentials to calculate the equilibrium constant (K) for the following balanced redox reaction at 25°C.

2Al (s) + 3Mg2 + (aq) ® 2 Al3 + (aq) + 3Mg (s)

The equation Eºcell = 0.0592/n logK must be used to find n and also Eºcell

2 Al (s) + 3 Mg2 + (aq) → 2 Al3 + (aq) + 3 Mg (s) Al3 + + 3e - - - > Al Eº = - 1.66 V Mg2 + + 2e - - - >Mg Eº = - 2.37V

To balance the equation, 6 moles of electrons must be transferred (2 Al and 3 Mg). This will be the value of n in the equation.

To find Eºcell, you need the reduction potentials which should be given in a table, and given above. Eºcell = - 1.66 - (-2.37) = 0.71 V log K = Eºcell x n/0.0592 = 0.71 x 6/0.0592 log K = 71.95 K = 10^71.95 K = 1.1x10^72