Effect of temperature on the partial molar volumes of some bivalent transition metal nitrates and magnesium nitrate in DMF + water mixtures

Abstract

Partial molar volumes of some bivalent transition metal nitrates viz; manganese nitrate, cobalt nitrate, nickel nitrate, copper nitrate, zinc nitrate, and magnesium nitrate have been determined in aqueous and aqueous mixtures of

dimethylformamide (5, 10, 15, 20 and 25% by weight of dimethylformamide) from solution density measurements at various temperatures and electrolyte concentrations. The data were evaluated by using Masson equation and the obtained parameters interpreted in terms of ion-solvent and ion-ion interactions. The partial molar volumes vary with temperature as a power series of temperature. Structure making/breaking capacities of the electrolytes have been inferred from the sign of [∂²ϕ_v⁰/∂<i>T</i>²]_p, i.e. second derivative of partial molar volume with respect to temperature at constant pressure. All the electrolytes have been found to act as structure breakers in aqueous as well as in aqueous dimethyl formamide mixtures.