Thermodynamic Study of the Ion‐Pairing of Some Transition Metal Perchlorates in Urea‐Water Mixtures from Conductivity Measurements

Abstract

AbstractThe conductivity of some transition metal perchlorates, M(ClO4)2 (M2+ = Mn, Co, Ni, Cu and Zn) has been measured in urea‐water mixtures at 288–318 K. The limiting molar conductivities and the ion association constants of these electrolytes were calculated by the Shedlovsky extrapolation method. The ion association constants de creased in the order Co > Ni > Zn with increasing the atomic number, whereas Cu > Mn in the ionic association constants as are suit of the maximum temperature dependencies of Cu2+.The thermodynamic functions, ΔH° and A S°, for the formation of that ion pair have also been obtained.Both ΔH° and ΔS° for all the salts under study are positive values. On the other hand, the Walden products, Δoη, of the salts in crease with an in crease in temperature at 288–318 K, which indicate that these electrolytes be have as structure‐makers or promotors. Also, the activation energies, E, have been calculated and discussed.