STUDIES OF RELAXATION EFFECTS IN ELECTROLYTIC SOLUTIONS WITH THE PRESSURE-STEP METHOD.
Technical rept. no. 27,
WESTERN RESERVE UNIV CLEVELAND OHIO ULTRASONICS RESEARCH LAB
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A pressure-step apparatus is described which permits the measurement of relaxation times of chemical processes involving ionic equilibria. The method involves the sudden release of an applied static pressure on an electrolytic solution. After the pressure release, the re-establishment of equilibrium between free hydrated ions and associated species is followed by means of conductance measurements. The relaxation time is observed directly from a display of the conductance changes on an oscilloscope screen. Relaxation times longer than 20 micro-sec can be measured with this apparatus. The method was applied to the study of complex formation between polyvalent cations and various ligands e.g., sulfate, malonate, glycollate, glycinate, acetate. Relaxation times ranging from about 100 micro-sec to several seconds were measured. For BeSO4, the dependence of the relaxation time upon temperature and solvent deuteration as well as pH and concentration was determined. Rate constants for the formation of inner sphere coordination complexes for nickel malonate and beryllium sulfate were determined. Author