Electrochemistry

 

 24) (a) H2(g) + F2(g) 2H+(aq) + 2F -(aq)

 

                     H2(g) 2H+(aq) + 2e-             E°red = 0.00 V      

             F2(g) + 2e- 2F -(aq)                       E°red = 2.87 V
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          H2(g) + F2(g) 2H+(aq) + 2F -(aq)     E° = 2.87 V

 

          E° = E°red(reduction) - E°red(oxidation) = 2.87 V - 0.00 V = 2.87 V

 

       (b) Cu(s) + Ba2+(aq) Cu2+(aq) + Ba(s)

 

                             Cu(s) Cu2+(aq) + 2e-          E°red = 0.337 V      

             Ba2+(aq) + 2e- Ba(s)                         E°red = -2.90  V
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          Cu(s) + Ba2+(aq) Cu2+(aq) + Ba(s)     E° = -3.24 V

 

          E° = E°red(reduction) - E°red(oxidation) = -2.90 V - 0.337 V = -3.24 V

 

       (c) 3Fe2+(aq) Fe(s) + 2Fe3+(aq)

 

              Fe2+(aq) + 2e- Fe(s)                        E°red = -0.440 V      

                     2Fe2+(aq) 2Fe3+(aq) + 2e         E°red = 0.771  V
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                      3Fe2+(aq) Fe(s) + 2Fe3+(aq)    E° = -1.211 V

 

          E° = E°red(reduction) - E°red(oxidation) = -0.440 V - 0.771 V = -1.211 V

 

       (d) Hg22+(aq) + 2Cu+(aq) 2Hg(l) + 2Cu2+(aq)

 

                    Hg22+(aq) + 2e- 2Hg(l)                          E°red = 0.789 V      

                              2Cu+(aq) 2Cu2+(aq) + 2e            E°red = 0.153 V
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          Hg22+(aq) + 2Cu+(aq) 2Hg(l) + 2Cu2+(aq)     E° = 0.636 V

 

          E° = E°red(reduction) - E°red(oxidation) = 0.789 V - 0.153 V = 0.636 V