UPTAKE OF NO3 ON KI SOLUTIONS - RATE COEFFICIENT FOR THE NO3- REACTION AND GAS-PHASE DIFFUSION-COEFFICIENTS FOR NO3(I)

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- r eaction to be k=(4.6+/-0.5)x10(9) M(-1) s(-1). It is suggested that th e reaction of NO3 with halide ions proceeds by electron transfer. Use of high concentration of KI enabled determination of the gas-phase dif fusion coefficients of NO3 in H2O vapor, He, N-2 and O-2 to be, respec tively, D-NO3-H2O=120+/-15, D-NO3-He=345+/-25 D-NO3-N2=80+/-15 and D-N O3-O2=80+/-15 Torr cm(2) s(-1). These coefficients agree well with cal culated values.