Q1.

The formal potential (E⁰) of the Fe3+/Fe2+ redox pair was measured in three kinds of acids with pH=0, and the following values were obtained. In which acid does the Fe3+ ion have the strongest oxidation power? In which acid does the Fe3+ ion form the strongest complex?

Q2.

The voltage between the two Cd electrodes in the following electrochemical cell was measured and it was -0.41 V at 25 degrees. If Cd2+ ions and CN-ions form Cd(CN)₄^2-, what is the equilibrium constant(Kf ,formation constant) of complex formation? Ignore the inter-liquid contact potential between the separators.

Cd l Cd²⁺(0.01M) ll Cd²⁺ (0.01M), CN^-(0.1M) / Cd

HCl;0.52V(vs. SCE) H2SO4;0.04V (vs. SCE) H3PO4;0.44V (vs. NHE)