2) List the following ionic species as electron donor in descending order. Icdot Ba^+2(E^aBa^2+/Ba_(0))=-2.906V) II-Cd^+2(E^acd^2+/Cd_(d)=-0.403V) IIIcdot Co^+3(E^circ Co^3+/Co^2+=1.808V) IVcdot Cu^+2(E^circ Cu^n/Cu_(0))=0.337V) A) Igt IIgt IIIgt IV B) IIgt Igt IVgt III C) Igt IIgt IVgt III D) IIIgt Ngt IIgt I E) IIIgt IVgt Igt II

To determine the order of ionic species as electron donors, we need to consider their standard reduction potentials. The higher the reduction potential, the more likely the species is to gain electrons and act as an electron donor.<br /><br />Given the standard reduction potentials:<br />- $I: Ba^{2+}/Ba = -2.906V$<br />- $II: Cd^{2+}/Cd = -0.403V$<br />- $III: Co^{3+}/Co^{2+} = 1.808V$<br />- $IV: Cu^{2+}/Cu = 0.337V$<br /><br />The order of ionic species as electron donors in descending order is:<br />$III > IV > I > II$<br /><br />Therefore, the correct answer is E) $III > IV > I > II$.