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45.
Based on the table above, which of the following pairs of reagents would react spontaneously in an oxidation-reduction reaction?
Before checking each choice against the table of oxidation potentials given, it would be most efficient, logically, to scan the choices and notice that choices B and C are two sides of the same redox reaction:
Mg + Mn2+ Mg2+ + Mn
Applying a fundamental concept now, that if the forward reaction is not spontaneous, then the reverse reaction must be (and vice versa), we can eliminate the other three choices; we need then only determine which of these two, B and C, is spontaneous as written. According to the tabulated values, the oxidation of magnesium, Mg, has a larger E° value, at 2.37 V, than does manganese, Mn, at 1.03 V; larger, more positive values of E° correspond to more favorable processes: the magnesium is the more likely candidate for oxidation, and choice B is therefore correct.
B Mg + Mn2+
OK...
am i crazy ? I thought the when there are both oxidatized/reduced. Which ever had the higher E value, would be reduced, while the lower would be oxidized. From this you would switch the E value sign for wherever you decided to change...
ahh.
anyone???
Based on the table above, which of the following pairs of reagents would react spontaneously in an oxidation-reduction reaction?
Before checking each choice against the table of oxidation potentials given, it would be most efficient, logically, to scan the choices and notice that choices B and C are two sides of the same redox reaction:
Mg + Mn2+ Mg2+ + Mn
Applying a fundamental concept now, that if the forward reaction is not spontaneous, then the reverse reaction must be (and vice versa), we can eliminate the other three choices; we need then only determine which of these two, B and C, is spontaneous as written. According to the tabulated values, the oxidation of magnesium, Mg, has a larger E° value, at 2.37 V, than does manganese, Mn, at 1.03 V; larger, more positive values of E° correspond to more favorable processes: the magnesium is the more likely candidate for oxidation, and choice B is therefore correct.
B Mg + Mn2+
OK...
am i crazy ? I thought the when there are both oxidatized/reduced. Which ever had the higher E value, would be reduced, while the lower would be oxidized. From this you would switch the E value sign for wherever you decided to change...
ahh.
anyone???
