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Unformatted text preview: A voltaic cell is constructed from a standard H + | H 2 half cell (E o red = 0.000 V) and a standard Br 2 | Br- half cell (E o red = 1.080 V). The cell voltage is V. Feedback: The spontaneous cell reaction is the one in which the strongest oxidizing agent is reduced at the cathode and the strongest reducing agent is oxidized at the anode . For a spontaneous cell reaction, E o cell will be positive. The strongest oxidizing agent has the largest standard reduction potential. The half-cell with the largest standard reduction potential is the cathode. Therefore, the strongest oxidizing agent is Br 2 , and the reduction reaction in the cathode compartment is: Br 2 (l) + 2 e- 2Br- (aq) E o red = 1.080 V The strongest reducing agent is paired with the oxidizing agent that has the smallest standard reduction potential. 2H + (aq) + 2 e- H 2 (g) E o red = 0.000 V Therefore, the strongest reducing agent is H 2 and the oxidation reaction in the anode compartment is: H 2 (g) 2H + (aq) + 2 e- E o ox = 0.000 V The oxidation potential is equal in magnitude and opposite in sign to the reduction potential. The spontaneous cell reaction is obtained by adding the two half reactions. If necessary, each half reaction is multiplied through by an integer so that the electrons will cancel. The half cell potentials represent potential differences and are NOT affected by this multiplication....
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