Kinetics of the Bromate-Bromide Reaction at High Bromide Concentrations

摘要

At bromide concentrations higher than 0.1 M,a second term must be added to the classical rate law of the bromate-bromide reaction that becomes-d[BrO_3~-]/dt=[BrO_3~-](H~+]~2(K_1[Br~-]+k_2[Br~-]~2).In perchloric solutions at 25 deg C,k_1=2.18 dm~3 mol~(-3) s~(-1) and k_2=0.65 dm~4 mol~(-4) s~(-1) at 1 M ionic strength and k_1=2.60 dm~3 mol~3 s~(-1)and k_2=1.05 dm~4 mol~(-4) s~(-1) at 2 M ionic strength.A mechanism explaining this rate law,with Br_2O_2 as key intermediate species,is proposed.Errors that may occur when using the Guggenheim method are discussed.