Part (b) is where I'm having an issue.
So the cathode reaction has a reduction potential of -0.83 V
The anode reaction (in the case of the formation of Oxygen) has a reduction potential = +1.23V
So Ereduced - Eoxidised = -0.83-1.23 = -2.06 V
However, the mark scheme gives a positive value....
What have I done wrong ?