Thermodynamic Investigation of Sodium Nitrate in N,N-dimethylformamide Aqueous Mixtures Based on Potentiometric Measurements at T = (298.2, 303.2, and 308.2) K.

In this work, thermodynamic properties of ternary (NaNO3 + DMF + water) system were reported using the potentiometric method. The electromotive force measurements were performed on the galvanic cell of the type: NO 3 - ISE NaNO 3 m , DMF w % , H 2 O (1 - w) % Na - ISE , in various mixed solvent systems containing 0, 5, 10, 15 and 20% mass fractions of DMF over total ionic strengths from 0.0100 to 2.500 mol·kg−1 at T = (298.2, 303.2 and 308.2) K and P = 0.1 MPa. The experimental activity coefficients of NaNO3 were analysed using extended Debye–Hückel equation, Pitzer ion interaction model and Scatchard equation. The Pitzer adjustable parameters were used to calculate γ ± , φ , G E / nRT , H E / nRT and S E / nR . Also, Scatchard parameters were used to calculate γ N 2 / γ N 1 for the whole series of under investigation system. [ABSTRACT FROM AUTHOR]