Question

what information do the reduction potentials of two elements give about a redox reaction between those elements

Answer 1

Answer: It tells us, if the substance will get oxidized or reduced.

Explanation:

The electrode reduction potential values of given substances determine the tendency to gain electrons.

If the species has negative reduction potential, it means that it will easily loose electrons and will be oxidized. Hence, it will be considered as a stronger reducing agent.

Similarly, if the species has positive reduction potential, it means that it will easily gain electrons and will be reduced. Hence, it will be considered as a stronger oxidizing agent.

For Example: The reduction potentials of $Zn^{2+}\text{ and }Cu^{2+}$ are given as:

$E^o_{Zn^{2+}/Zn}=-0.76V$

$E^o_{Cu^{2+}/Cu}=+0.34V$

Thus, if a reaction occurs between zinc and copper, zinc with negative reduction potential will easily loose electrons and will act as anode. Copper with positive reduction potential will easily gain electrons and will act as cathode.

Hence, the reduction potential will tell us, if the substance will get oxidized or reduced.

Answer 2

with redox reactions you determine if you need to add electrons and water to the different sides depending what half is oxidation and reduction