In making printed circuit boards, ferric chloride (FeCl3) solution is used to etch (corrode) exposed copper on a polymer (plastic) substrate.

(a) From the following data, calculate the potential of the cell inducing etching (corrosion):

Standard Potential Cu2+/Cu = 0.34; Standard potential Fe3+/Fe2+ = 0.77 volt; activity Fe3+ = 1; activity Fe2+ = 0.001; activity Cu2+ = 0.001

(b) if the same solution is used to etch many boards, copper ions will start to build up in solution and the activity of Fe3+ will decrease until corrosion no longer occurs. Calculate the value of aFe3+/aFe2+ when the copper ion activity is 1.

a = activity

I am having trouble setting up the half reactions and full corrosion equation because of the charges and also not sure what question 2 means.

Thank you!