4) apply the Nernst equation and calculate the concentration of Pb2+
Find the literature values for Eored of Pb2*/Pb(s) and Fe? /Fe(s). Based on that data, predict the E°on for the following voltaic cell; show your work Fe(s) | Fe?(1M) I| Pb2(1M) | Pb(s) Using the literature Eãed values and applying the Nernst equation, calculate the concentration of Pb2 needed to make the following battery: · Pb(s) | Pb2 (unknown concentration) I| Pb2 (1M) | Pb(s) Enn = 0.059 V
B. Use the table of standard reduction potentials below to identify the metal or metal ion that is the strongest oxidizing agent.
Half-reaction
Pb4+ + 2 e- ® Pb2+
+1.80
Au3+ + 3 e- ® Au
+1.50
Fe3+ + 3 e- ® Fe
+0.771
I2 + 2 e- ® 2 I-
+0.535
Pb2+ + 2 e- ® Pb
-0.124
Al3+ + 3 e- ® Al
-1.66
Mg2+ + 2 e- ® Mg
-2.37
K+ + e- ® K
-2.93
a.
Pb4+
d.
K
b.
Pb2+
e.
Al
c.
K+
C. Silver tarnish (Ag2S) can be removed by immersing silverware in a hot solution of baking soda (NaHCO3) in a pan lined with aluminum foil; however, foul-smelling hydrogen sulfide gas (H2S) is produced. Which of the following statements is correct?
Silver/silver(I)
+0.799
Sulfur/hydrogen sulfide
+0.141
Aluminum/aluminum(III)
-1.662
Sodium/sodium(I)
-2.713
a.
Aluminum ions react with S2-, form aluminum sulfide, and gaseous carbon dioxide is released.
b.
Silver ions in the presence of the baking soda (NaHCO3) oxidize sulfide to elemental sulfur that attacks the aluminum foil, which produces aluminum sulfide.
c.
The aluminum acts as a reducing agent for the silver(I) in silver sulfide; then bicarbonate ion protonates the sulfide ion that is released.
d.
Aluminum is plated onto the silver surface, making it shiny again, and then the reaction of bicarbonate with aluminum oxide releases CO2.
e.
Silver in Ag2S reduces the aluminum, becomes metallic silver in the process, and releases hydrogen sulfide, H2S.
D. Using the following data, determine the standard cell potential for the electrochemical cell constructed using the following reaction: Zn(s) + Pb2+(aq) ® Zn2+(aq) + Pb(s).
Half-reaction Standard reduction potential
Zn2+(aq) + 2 e- ® Zn(s) -0.763
Pb2+(aq) + 2 e- ® Pb(s) -0.126
a.
+0.637 V
d.
-0.889 V
b.
-0.637 V
e.
+0.889 V
c.
+1.274 V
E. Based on the information in the table of standard reduction potentials below, what is the standard cell potential for an electrochemical cell that has iron (Fe) and magnesium (Mg) electrodes immersed in 1M Fe3+ and Mg2+ solutions? Also, identify the cathode.
