Concise Physical Chemistry

(Tina Meador) #1

c14 JWBS043-Rogers September 13, 2010 11:27 Printer Name: Yet to Come


234 ELECTROCHEMICAL CELLS

one can obtain the following voltages at very small HCl(aq) concentrations

mol dm−^3 Ecell(volts)

0.00321 0.5205
0.00562 0.4926
0.00914 0.4686
0.0134 0.4497
0.0256 0.4182

Find the standard cell potential of the Ag(s);AgCl(s) half-cell.

Problem 14.9
It is proposed to use cerium(III) as a reducing agent in the redox titration of iron(III)
according to the reaction

Ce^3 +(aq)+Fe^3 +(aq)→Ce^4 +(aq)+Fe^2 +(aq) 1 MH 2 SO 4

The half-cell potentials written as reductions are somewhat modified in the strong
acid solution:

Ce^4 +(aq),Ce^3 +(aq); Pt is− 1 .44 volts 1 M H 2 SO 4

and

Fe^3 +(aq),Fe^2 +(aq); Pt is 0.68 volts 1 M H 2 SO 4

Is this a plausible titration method for further development? If so, why? If not, why
not?
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