Behaviour of the series resonant frequency in electrolyte solutions

In this work, the series resonance frequency is studied in different electrolytic mediums. The frequency changes with NaCl, KCl, KNO3, MgCl2, CuSO4 and K3[Fe(CN)6] aqueous solutions were measured. Conductivity, but not the electrolyte concentration, is the responsible of those changes. Another evidence of this relation is the frequency behaviour when a KNO3 was heated from 15 °C to 50 °C. The frequency changes are in agreement with our theoretical predictions. Also, the influence of solvent nature in the relation between frequency and conductivity is reported. This was studied with LiCl solutions in water, formamide, methanol, ethanol and dimethyl sulfoxide. Finally, a comparison between changes by conductivity and density/viscosity is reported. In all cases, the conductivity is an important factor in the series resonance frequency changes.