The effect of temperature on association constants and conductivities of ferrous chloride and ferric chloride in DMF-water mixtures

Abstract

Conductance measurements at five different temperatures varying from 288.15 to 328.15 K were performed for ferrous chloride (FeCl₂) and ferric chloride (FeCl₃) in 20-80 wt % in N,N-dimethylformamide (DMF)-water mixture. To analyze conductivity data, density and viscosity values of the DMF-water mixtures have been determined experimentally at the same temperatures. The conductivity data has been analyzed using the Kraus-Bray and Shedlovsky models. The limiting equivalent conductance values, the association constants (K_A), thermodynamic parameters of association (Gibbs energy, enthalpy and entropy changes) for FeCl₂ and FeCl₃ were calculated and discussed depending on temperature and the composition of solvent mixture.