EXPERIMENT
Four trials with an increasing concentration of hypochlorite (0.5, 1, 2, and 3 mL for Trials 1−4, respectively) and constant concentration of the dye were performed. Aside from the change described below, the experimental protocol suggested by Henary and Russell was employed. All data was collected on a Shimadzu UV-2600 UV−vis spectrophotometer using polystyrene cuvettes with a 10 mm path length.
Pseudorate constants obtained using the original protocol1 showed poor proportionality to [OCl−] (Table 1). This problem appears to stem from the use of deionized water to dilute the solutions to the final volume. Doing so changes the ionic strength, a variable that is not accounted for. In order to maintain a constant ionic strength for all trials, 1.6 M NaCl2 was substituted for deionized water in diluting the solutions to the final volume (Figure 1). This change resulted in an improved proportionality between k′ and [OCl−] (Table 1)