Conductivity, apparent molar volume and isentropic compressibility of 12-tungstosilicic acid and potassium 12-tungstosilicate in aqueous solutions at different temperatures

12-Tungstosilicic acid and potassium 12-tungstosilicate were synthesized and conductivities, densities and ultrasound velocities of their aqueous solutions were studied in the 283.15–303.15 K temperature range at 5 K intervals. Apparent molar volume and apparent molar isentropic compressibility of 12-tungstosilicic acid and potassium 12-tungstosilicate and isentropic compressibility of the studied aqueous solutions have been determined from the experimental density and sound velocity data.