Heat capacity and density of potassium iodide solutions in mixed N-methylpyrrolidone-water solvent at 298.15 K

Abstract

The heat capacity and density of potassium iodide solutions in a mixed N-methylpyrrolidone (MP)-water solvent with a low content of the organic component are measured via calorimetry and densimetry at 298.15 K. Standard partial molal heat capacities \(\bar C_{p,2}^ \circ \) and volumes \(\bar V_2^ \circ \) of potassium iodide in MP-water mixtures are calculated. Standard heat capacities \(\bar C_{p,i}^ \circ \) and volumes \(\bar V_i^ \circ \) of potassium and iodide ions are determined. The character of the changes in heat capacity and volume are discussed on the basis of calculating additivity coefficients δc and δv upon the mixing of isomolal binary solutions KI-MP and KI-water, depending on the composition of the MP-H2O mixture and the concentration of the electrolyte.