Abstract
Densities of aqueous solutions of nitric acid at concentrations from (0.025 to 36) mol·kg–1 (0.16–70% w/w) have been determined by high precision vibrating-tube densitometry. Measurements over the temperature range of 293.15 ≤ T/K ≤ 343.15 were made at 5 K intervals at atmospheric pressure with a commercial apparatus, using an improved measurement protocol. Special attention was given to the dilute concentration region to determine the (conventional) standard partial volume of the nitrate ion. Measurements at higher temperatures (323.15 ≤ T/K ≤ 473.15) were made at seven temperatures at a pressure of 2.0 MPa using a custom-built high-temperature densimeter. For these measurements, the nitric acid concentration was restricted to 15 mol·kg–1 (50% w/w) to minimize the risk of corrosion. The present results greatly expand density and volumetric databases for the aqueous solutions of this critical reagent.