Ultrasonic Relaxation Studies in Aqueous Solutions of 2–2 Electrolytes

Abstract

The ultrasonic absorption in aqueous solutions of a number of 2–2 electrolytes including the sulfates of the bivalent transition metal ions has been measured in the frequency range 105–109 Hz at temperatures between 5 and 50°C. Generally, three relaxations can be separated in this frequency range if the structural absorption of the electrolytic solution is properly taken into account. Relaxation times and corresponding maximum absorption per wavelength are allocated to the normal coordinates of a three-step association or dissociation mechanism. In order to be applicable to the new experimental results, the existing theory of the stepwise association had to be extended to a more general form. By means of suitable transformations the normal coordinates can then be expressed in terms of kinetic and thermodynamic parameters of the individual reaction steps. Values of the rate constants, equilibrium constants, reaction volumes, and activation energies calculated on the basis of the extended theory are presented for the individual reaction steps.

When spectroscopy fails: The measurement of ion pairing

“…Good-quality studies by both DRS [29] and USR [30,31] exist for the Ni 2+ /SO 4 2-system. DRS detects all three ion pair types: 2SIPs, SIPs, and CIPs, as shown in the dielectric loss spectrum, Fig.…”

Point Defects and Their Interaction

“…In this manner, the equilibrium constant of reaction 17 has been found to be 4.5.10-3 mole/liter (41) . Similarly, the formation of the complex Be(OH2hS04 has been investigated (42,43).…”

Acid dissociation constants and rates as studied by ultrasonic absorption

“…c curve may make it impossible to exclude a fit using the K, (ultrasonic), 0.005. Nevertheless, data on MgS04 also suggest that it may not be valid to assume the AVO of 1 $ 2 to be the largest (35).…”

“…ref. 35. It would also not be the case for ion pairing involving protons in non-aqueous solvents such as dimethyl sulfoxide or dimethyl formamide (20).…”