Question

The lab name is Electrochemical Determination of entropy of mixing

Explain briefly why complementary solutions were used in this experiment. How does this experimental design effectively simulate the hypothetical reversible mixing process discussed earlier in the notes( earlier in the notes I put reversible happen infinitesimally slow)? What is wrong with measuring the voltage of a cell containing only one solute component on each side (i.e., Fe(II) of a given molality on one side and Fe(III) with the same molality on the other)?

Answer 1

Explain briefly why complementary solutions were used in this experiment.
For the given cell reaction of complimentary solutions,
Pt | K4Fe(CN)6 (m1), K3Fe(CN)6 (m2) || K3Fe(CN)6 (m3), K4Fe(CN)6 (m4) | Pt
m1 = m3; m2 = m4.
Complimentary cells are used to cancel the concentration term in Nerst equation and express in terms of only two concentrations.

How does this experimental design effectively simulate the hypothetical reversible mixing process
discussed earlier in the notes( earlier in the notes I put reversible happen infinitesimally slow)?

having same activity coefficients

What is wrong with measuring the voltage of a cell containing only one solute component on each side
(i.e., Fe(II) of a given molality on one side and Fe(III) with the same molality on the other)?

To have redox reactions in each half cell, two components having different reduction potentials are required. One component cannt make a half cell