Cell potentials & Redox Titrations

1. What is the potential for the galvanic cell depicted below:


Pt_(s) | N₂H₅+ (2.59 mM), NH₄+ (9.01 mM), pH 5.21 || Pb2+ (15.06 mM), pH 4.88 | PbO_2(s) | Pb_(s)

1. A galvanic cell, depicted in line notation below, has been prepared to determine the K_a of a weak base. The sodium salt of the base (NaB) is added to the cathode where is reacts with water. The cell potential is measured to be –1.001 V. Determine the K_a for this unknown base, keeping in mind that neither the Na+, B– or BH are redox active.


Pt_(s) | I₃– (82.10 mM), I– (17.34 mM) || SO₃2– (45.21 mM), S₂O₃2– (67.20 mM), NaB (16.90 mM)

1. A solution containing ClO₃– is to be analyzed by a redox titration. Which of the titrant options below could effectively reduce ClO₃–, through the half reaction scheme below?


ClO₃– + 2H+ + e– ⇌ ClO₂ + H₂O E° = 1.130 V


1. You have a 40.00 mL solution that contains 25.00 mM perchlorate (ClO₄–), buffered to a pH of 3.65. You reduce the perchlorate by titrating it with a solution of 160.0 mM ruthenium(II) (Ru2+). During the course of the titration you record the cell potential using a platinum cathode, and a S.C.E., what potentials will you measure at each of the titration volumes listed below?