Question

Calculate the standard electrode potential for the redox reaction that occurs when a silver electrode is placed in a solution containing 0.1 M Ag+ ions and a platinum electrode is placed in a solution containing 0.1 M H+ ions at standard conditions. The reduction half-reaction for Ag+ is Ag+ (aq) + e- → Ag(s), and the reduction half-reaction for H+ is H+ (aq) + e- → 1/2 H2 (g).

Answer 1

To calculate the standard electrode potential for the redox reaction, we need to find the standard reduction potentials for both half-reactions and then combine them.The standard reduction potential for the Ag+ half-reaction is given as:Ag+  aq  + e-  Ag s    E Ag+/Ag  = +0.80 VThe standard reduction potential for the H+ half-reaction is given as:H+  aq  + e-  1/2 H2  g    E H+/H2  = 0.00 V  by definition, hydrogen electrode is the reference electrode Now, we need to determine which half-reaction is the reduction and which is the oxidation. Since the Ag+ half-reaction has a more positive reduction potential, it will proceed as a reduction. The H+ half-reaction will proceed as an oxidation, so we need to reverse the reaction and change the sign of its standard reduction potential:1/2 H2  g   H+  aq  + e-   E H2/H+  = -0.00 VNow, we can calculate the overall standard electrode potential  Ecell  for the redox reaction by adding the standard reduction potentials of the two half-reactions:Ecell = E Ag+/Ag  + E H2/H+ Ecell = +0.80 V +  -0.00 V Ecell = +0.80 VSo, the standard electrode potential for the redox reaction is +0.80 V.