Solving Redox Equations: Cathodic Reaction of Oxygen

[big man]

Homework Statement

Write the half equation for the cathodic reaction of oxygen

The Attempt at a Solution

Now I know that the cathodic reaction will be reduction and so the oxygen will be gaining electrons. I thought I had the answer from the lecture notes, but then I thought of another possible equation that would work too and I don't know which one is right??

The two equations are as follows:
equation from notes( the notes say that this is the most common)
$$O_2 + 2H_2O + 4e^- ->4OH^-$$

the equation I came up with
$$O_2 + 4H^+ + 4e^- ->2H_2O$$

Are these just two possible half equations for the cathodic reaction of oxygen or is one wrong??

Thanks for your time

 

[Gokul43201]

I think we need more context here. Both reactions are legal, and likely occur at quite different potentials, so additional details are necessary.

 

[Blueshift5]

and help

Both of the equations you have written are correct half equations for the cathodic reaction of oxygen. The first equation is known as the alkaline equation, which is commonly used in basic solutions. The second equation is known as the acidic equation, which is commonly used in acidic solutions. Both equations represent the reduction of oxygen, where it gains electrons. The choice of which equation to use depends on the specific conditions of the reaction. It is important to note that these equations are half reactions and must be combined with a corresponding anodic reaction to form a complete redox equation. I would recommend consulting with your instructor or referencing a reliable source to determine which equation is appropriate for your specific situation.