ISSN:
1572-8927
Keywords:
DCl
;
D2
;
deuterated hexanol
;
emf
;
equilibrium constants
;
isotope exchange
;
standard electrode potential
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract This paper reports our results for the direct experimental determination of the equilibrium constant for the hydrogen-isotope-exchange reaction, 1/2D2(g)+HCl(hexOH)=1/2H2(g)+DCl(hexOD), where hexOH isn-hexanol and hexOD isn-hexanol with deuterium substitution in the alcohol function. The reaction was studied in electrochemical double cells without liquid junction for which the net cell reaction is the above isotope-exchange reaction. The experimentally determined value of ε° (296.0°K) for this cell is 4.03±0.95 mV (strong electrolyte standard states, mole-fraction composition scale); the value of the equilibrium constant for the reaction is 1.17±0.05. The contributions of isotope-exchange and transfer effects to the magnitude of the standard Gibbs energy change for the above reaction and for the analogous reaction 1/2D2(g)+HCl(aq)=DCl(daq)+1/2H2(g) are considered. Our results support the conclusion of Heinzinger and Weston that the formulation of the solvated proton in water as H3O+, as opposed to H9O4 +, is sufficient for the interpretation of the thermodynamics of hydrogen-isotope-exchange reactions in water. We also find that the formulation of the solvated proton inn-hexanol as ROH 2 + is sufficient for the interpretation of our results on the thermodynamics of hydrogen-isotope-exchange inn-hexanol.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00648895
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