Evaporation kinetics of ammonium chloride solution droplets in water vapor

Abstract The evaporation kinetics of aqueous NH 4 Cl droplets have been measured in a single-particle suspension apparatus in conjunction with Mie resonance spectroscopy. Evaporation coefficients for NH 3 and HCl, heretofore inaccessible to any measurements, have been deduced from the droplet evaporation rate data using a mathematical model considering equal-molar evaporation of the solute gases. The values are 0.29 ± 0.03 for NH 3 and 0.45 ± 0.04 for HCl, based on the partial pressures of the solute gases estimated from the best available thermodynamic properties.