Why do we tend to measure reduction potential instead of oxidation potential?  [ENDORSED]

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Hannah Lee 2F
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Why do we tend to measure reduction potential instead of oxidation potential?

Postby Hannah Lee 2F » Thu Feb 27, 2020 4:35 pm

Why do we tend to measure reduction potential instead of oxidation potential? Is there ever a situation in which we would use oxidation potentials?

Chem_Mod
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Re: Why do we tend to measure reduction potential instead of oxidation potential?  [ENDORSED]

Postby Chem_Mod » Thu Feb 27, 2020 6:20 pm

The potentials are measured as either reducing or oxidizing half-reactions (whichever one is the favored positive voltage redox reaction in the experiment/measurement).
The favored (positive voltage) is always the one that occurs by itself.

However they are listed in tables as reduction half-reactions.

In class I said they could be listed as either reduction half-reactions or oxidation half-reactions.
The convention was taken to list them as reduction half-reactions.

To obtain the oxidation half-reaction reverse the reduction half-reaction from the table and change the sign of the standard cell potential, Eo.

Hope this helps.
:-)

Leila_4G
Posts: 114
Joined: Sat Sep 14, 2019 12:17 am

Re: Why do we tend to measure reduction potential instead of oxidation potential?

Postby Leila_4G » Thu Feb 27, 2020 8:20 pm

Thank you.
On a related note, why do both the half reactions cell potential of the oxidation of 2Cl- and the reduction of Cl2 equal the same number? In my discussion today we did a problem like that and the cell potentials were not opposite signs of each other.


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