1Here are the standard reduction potentials for 2 half-reactions that occur in a rechargeable Ni/Cd battery. What is the standard cell potential?-0.81 volts Cd(s) + 2OH-(aq) + 2e-Cd(OH)2(s)+0.44 volts Ni(OH)3(s) + e-Ni(OH)2(s) + OH-(aq) Go= - n F EoFor a spontaneous reaction, you needGo< 0 and Eocell> 0.A) – 1.25 VB) + 1.25 VC) – 0. 37 VD) + 0.37 V2The half-reaction with the more positive reduction potential produces the greater decrease in free energy, so it runs as written, i.e. as a reduction reaction.-0.81 volts Cd(OH)2(s) + 2e-Cd(s) + 2OH-(aq)+0.44 volts Ni(OH)3(s) + 1 e-Ni(OH)2(s) + OH-(aq) EoredGo= - n F EoThe other half-reaction then must reverse and run as an oxidation reaction.If a reaction reverses, both Goand Eochange sign. Eocell= Eoreduction+ Eooxidation=+1.25 VEooxidation= - Eoreduction
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