Ultimately, values must be based on experimental results;

Chapter 20, Problem 102

(choose chapter or problem)

Ultimately, values must be based on experimental results; in many cases, these experimental results are themselves obtained from values. Early in the twentieth century, G. N. Lewis conceived of an experimental approach for obtaining standard potentials of the alkali metals. This approach involved using a solvent with which the alkali metals do not react. Ethylamine was the solvent chosen. In the following cell diagram, Na(amalg, 0.206%) represents a solution of 0.206% Na in liquid mercury. 1. Although Na(s) reacts violently with water to produce at least for a short time, a sodium amalgam electrode does not react with water. This makes it possible to determine for the following voltaic cell. 2. H21g, 1 atm2 Ecell = 1.8673 V Na1amalg, 0.206%2 Na+11 M2 H+11 M2 Ecell H21g2, Ecell = 0.8453 V Na1s2 Na+1in ethylamine2 Na1amalg, 0.206%2 E Gf Ecell E3Ag cell +4 Ag+1aq2 + I-1aq2 AgI1s2 AgNO3 Ecell when 3Ag+4 = x. 3Ag+4 = 1 M? Ecell Pt1s2 H21g, 1 atm2 H+11 M2 Ag+1x M2 Ag1s2 (a) Write equations for the cell reactions that occur in the voltaic cells (1) and (2). (b) Use equation (20.14) to establish for the cell reactions written in part (a). (c) Write the overall equation obtained by combining the equations of part (a), and establish for this overall reaction. (d) Use the value from part (c) to obtain for the overall reaction. From this result, obtain Compare your result with the value listed in Appendix D.