Using the following standard reduction potentials, determine the oxidation-reduction reaction that will occur spontaneously.
Al^3+ + 3e^- -------> Al E=-1.66V
Mg^2+ + 2e^- -------> Mg E=-2.73V
Al^3+ + 3e^- -------> Al E=-1.66V
Mg^2+ + 2e^- -------> Mg E=-2.73V
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A positive voltage will result in a spontaneous reaction.
(ΔG = -nFE)
(when ΔG <0, reaction is spontaneous)
You have to reverse the direction and the voltage one of the reactions so one produces electrons and one requires electrons.
Changing the most negative one in this case will result in a positive voltage.
Al^3+ + 3e^- -------> Al E= -1.66V
Mg -------> Mg^2+ + 2e^- E= +2.73V
voltage = 1.07V.
(ΔG = -nFE)
(when ΔG <0, reaction is spontaneous)
You have to reverse the direction and the voltage one of the reactions so one produces electrons and one requires electrons.
Changing the most negative one in this case will result in a positive voltage.
Al^3+ + 3e^- -------> Al E= -1.66V
Mg -------> Mg^2+ + 2e^- E= +2.73V
voltage = 1.07V.
-
Al will occur spontaneously
Mg will not.
Mg will not.