The decomposition of Bromodichloroacetate BrCl2CCO2- is an important required step in water purification. The kinetics of such decomposition has been presented in Chemical Reviews, November 2001. There are two possible pathways for these reactions, one unimolecular and the other bimolecular with the help of OH- ions.
Path 1. BrCl2CCO2- + H2O goes to CHCl2Br + HCO3-
With a pseudo-first-order rate constant k1=1.6 x 10-6 1/sec
Path 2. BrCl2CCO2- + OH- goes to Cl2OHCCO2- + Br-
With a second-order rate constant k2=2.4x10-4 1/(M sec)
(a) Write the overall rate law for the disappearance of BrCl2CCO2.
(b) What is the ratio of the rates for paths 1 and 2 at pH=7?
(c) At what pH would the rate for path 2 be 10% of the rate for path 1?