Finding the Standard Reduction Potential for Pd2+/Pd in an Electrochemical Cell

[geffman1]

An electrochemical cell of notation Pd|Pd2+ || Ni2+ |Ni has Eo = -1.45 V. If we know that the standard reduction potential of Ni2+ /Ni is Eo = -0.25 V, what is the standard reduction potential for Pd2+/Pd?

hey guys. this is my working
Ecell=reduction-oxidation
therefore Pd is anode therefore oxidisin and Ni is cathode therefore reducin.
so i sub this into formula -1.45=-0.25-oxidation therefore oxidation=-1.20 however the answer is positive 1.20, why is this? anyhelp would be good thanks

 

[vertciel]

Hello there,

This can be considered as a "tricky" question. I did not arrive at the right answer on my first try.

You have to read the question carefully. Although you calculated the standard OXIDATION potential for Pd -> Pd²⁺ + 2e^- correctly, you are asked for this half-reaction's standard REDUCTION potential (and NOT oxidation potential). Therefore, the correct answer is -(-1.20) = 1.20.

I hope that this helps!

 

[geffman1]

thanks mate, cleared that problem up good. thanks again