Answer: 2.3 seconds

Note that seawater (which is the ballast water in this case) contains on average 8.0 x 10-4 mol/L of bromide (Br), and has a typical pH of 8. HOCI and OClreact with Br according to the following reactions: HOCI + Br HOBr + C1 (with second-order rate constant ki = 1.6 x 103 M-'s-1) OCI + Br OBr + Cl (with second-order rate constant k2 = 9.0 x 10-4 M 's-1) [HOBr]t = [HOBr] + [OBr] Determine the half-life for the overall reaction of free chlorine with Br at 25 C, assuming [HOCI]I