Estimate E°_cell for the half reaction. 2H₂O + 2e^- → H₂ + 2OH^- given the following values of ΔG^o_f :

H₂O(l) = –237 kJ/ mol H₂(g) = 0.0 OH^-(aq) = –157 kJ/ mol e^- = 0.0 Compare this value of E°_cell with the value of E°_cell given in Table.

Table

 

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Standard Reduction Potentials at 25°C (298 K) for Many Common Half-reactions Half-reaction g° (V) Half-reaction * (V) O2 + 2H20 + 4e- - 40H- Cu2+ + 2e Cu Hg2Cl2 + 2e- 2Hg + 2CI- ARCI + e Ag + Cl- So- + 4H* + 2e- → H,SO, + H20 Cu2+ + e- → Cu* 2H* + 2e" Fel+ + 3e- - Pb2+ + 2e- Sn2+ + 2e- Ni2* + 2e- → Ni PbSO, + 2e- → Pb + SO,2- Cd2+ + 2e- F2 + 2e- → 2F- Ag+ + e Ag* Co+ + e- → Co+ 2.87 0.40 1.99 0.34 1.82 H2O, + 2H* + 2e → 2H,0 Ce+ + e- → Ce+ 1.78 1.70 0.27 0.22 0.20 PbO, + 4H* + SO2- + 2e PbSO, + 2H20 MnO,- + 4H* + 3e- → MnO, + 2H;0 10,- + 2H+ + 2e- IO;- + H20 MnO,- + 8H* + Se- + Mn2+ + 4H;0 Au+ + 3e" - Au PbOz + 4H* + 2e- → Pb?+ + 2H,0 C2 + 2e Cr,02- + 14H* + 6e- - O2 + 4H+ + 4e- MnO, + 4H* + 2e- IO;- + 6H* + Se → 2 + 3H20 Brz + 2e- + 2Br- VO* + 2H* + e" VO2+ + H,0 AuCl," + 3e" - Au + 4CI- NO;- + 4H* + 3e- → NO + 2H;0 CIO2 + e- → 2Hg+ + 2e- Hg+ Ag* + e + Ag Hgz2* + 2e- → 2Hg Fe+ + e Fe2+ O2 + 2H* + 2e" MnO,- + e - MnO2- I + 2e 21- Cu* + e- - Cu 1.69 1.68 1.60 1.51 1.50 0.16 0.00 -0.036 Н Fe Pb Sn -0.13 -0.14 1.46 1.36 1.33 -0.23 -0.35 -0.40 + 20- 2Cr* + 7H,0 - Cd Fe - 2H,0 Mn2* + 2H;0 Fe2* + 2e- Cr3+ + e + Cr+ Cr+ + 3e- - Cr Zn2+ + 2e - Zn 2H;0 + 2e- Mn2+ + 2e" - Mn Al3+ + 3e Al H2 + 2e- Mg+ + 2e - Mg La+ + 3e- La Nae INa Ca2+ + 2e - Ca Ba?+ + 2e" - Ba 1.23 1.21 -0.44 -0.50 1.20 1.09 1.00 -0.73 -0,76 H2 + 20H- -0.83 0.99 0.96 0.954 -1.18 -1.66 -2.23 + 2H- 0.91 0.80 0.80 -2.37 -2.37 0.77 0.68 -2.71 -2.76 -2.90 H,O2 -2.92 -3.05 0.56 K+ + e- → K Lit +e + Li 0.54 0.52 Standard Reduction Potentials at 25°C (298 K) for Many Common Half-reactions Half-reaction g° (V) Half-reaction * (V) O2 + 2H20 + 4e- - 40H- Cu2+ + 2e Cu Hg2Cl2 + 2e- 2Hg + 2CI- ARCI + e Ag + Cl- So- + 4H* + 2e- → H,SO, + H20 Cu2+ + e- → Cu* 2H* + 2e" Fel+ + 3e- - Pb2+ + 2e- Sn2+ + 2e- Ni2* + 2e- → Ni PbSO, + 2e- → Pb + SO,2- Cd2+ + 2e- F2 + 2e- → 2F- Ag+ + e Ag* Co+ + e- → Co+ 2.87 0.40 1.99 0.34 1.82 H2O, + 2H* + 2e → 2H,0 Ce+ + e- → Ce+ 1.78 1.70 0.27 0.22 0.20 PbO, + 4H* + SO2- + 2e PbSO, + 2H20 MnO,- + 4H* + 3e- → MnO, + 2H;0 10,- + 2H+ + 2e- IO;- + H20 MnO,- + 8H* + Se- + Mn2+ + 4H;0 Au+ + 3e" - Au PbOz + 4H* + 2e- → Pb?+ + 2H,0 C2 + 2e Cr,02- + 14H* + 6e- - O2 + 4H+ + 4e- MnO, + 4H* + 2e- IO;- + 6H* + Se → 2 + 3H20 Brz + 2e- + 2Br- VO* + 2H* + e" VO2+ + H,0 AuCl," + 3e" - Au + 4CI- NO;- + 4H* + 3e- → NO + 2H;0 CIO2 + e- → 2Hg+ + 2e- Hg+ Ag* + e + Ag Hgz2* + 2e- → 2Hg Fe+ + e Fe2+ O2 + 2H* + 2e" MnO,- + e - MnO2- I + 2e 21- Cu* + e- - Cu 1.69 1.68 1.60 1.51 1.50 0.16 0.00 -0.036 Н Fe Pb Sn -0.13 -0.14 1.46 1.36 1.33 -0.23 -0.35 -0.40 + 20- 2Cr* + 7H,0 - Cd Fe - 2H,0 Mn2* + 2H;0 Fe2* + 2e- Cr3+ + e + Cr+ Cr+ + 3e- - Cr Zn2+ + 2e - Zn 2H;0 + 2e- Mn2+ + 2e" - Mn Al3+ + 3e Al H2 + 2e- Mg+ + 2e - Mg La+ + 3e- La Nae INa Ca2+ + 2e - Ca Ba?+ + 2e" - Ba 1.23 1.21 -0.44 -0.50 1.20 1.09 1.00 -0.73 -0,76 H2 + 20H- -0.83 0.99 0.96 0.954 -1.18 -1.66 -2.23 + 2H- 0.91 0.80 0.80 -2.37 -2.37 0.77 0.68 -2.71 -2.76 -2.90 H,O2 -2.92 -3.05 0.56 K+ + e- → K Lit +e + Li 0.54 0.52