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LABORATORT 27 5. A voltaic cell is constructed by immersing a strip of lead meta

ID: 588153 • Letter: L

Question

LABORATORT 27 5. A voltaic cell is constructed by immersing a strip of lead metal in a 1.0MPb(NO) solution and a strip of cadmium metal in a 1.0 M Cd(NO), solution. The circui is completed by a wire and a salt bridge in the usual way, Anawer questions a-e a. Write the balanced overall net-ionic cell reaction. b. What is the cell potential for the voltaic cell described above c. Write the balanced net-ionic half-reaction that is occurring at the cathode. d. Write the balanced net-ionic half-reaction that is occurring at the anode. What would be the potential of the cell if it was modified to use a 0.10 M Pb(NO), solution and a 0.20 M Cd(NO), solution instead e.

Explanation / Answer

at anode

Cd(s) --------------------> Cd^2+ (aq) + 2e^-   oxidation half reaction

at cathode

Pb^2+ (aq) +2e^- ----------------> pb(s)            reduction half reaction

Cd(s) --------------------> Cd^2+ (aq) + 2e^-

Pb^2+ (aq) +2e^- ----------------> Pb(s)

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Cd(s) + Pb^2+ (aq) ------------> Cd^2+ (aq) + Pb(s) net overall reaction

Cd(s) --------------------> Cd^2+ (aq) + 2e^-       E0 = 0.40v

Pb^2+ (aq) +2e^- ----------------> Pb(s)          E0 = -0.13v

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Cd(s) + Pb^2+ (aq) ------------> Cd^2+ (aq) + Pb(s)     E0 cell = 0.27v

n= 2

E cell   = E0cell - 0.0592/n logQ

          = 0.27 -0.0592/2 log[Cd^2+]/[Pb^2+]

        = 0.27-0.0296log0.1/0.2

       =0.27-0.0296*-0.3010

      = 0.2789v >>>answer