Uptake of NO3 on KI solutions: rate coefficient for the NO3 + I− reaction and gas-phase diffusion coefficients for NO3

Uptake of NO3 by KI solutions was measured at 273 ± 1 K using a wetted-wall flow tube to determine the rate coefficient for the NO3(aq) + I− reaction to be k = (4.6 ± 0.5) × 109M−1 s−1. It is suggested that the reaction of NO3 with halide ions proceeds by electron transfer. Use of high concentration of KI enabled determination of the gas-phase diffusion coefficients of NO3 in H2O vapor, He, N2 and O2 to be, respectively, DNO3 − H2O = 120 ± 15, DNO3 − He = 345 ± 25DNO3 − N2 = 80 ± 15 and DNO3 − O2 = 80 ± 15 Torr cm2s−1. These coefficients agree well with calculated values.