Chemical Kinetics

The Bromate-Bromide Reaction


You are a researcher studying the kinetics of the reaction between bromide and bromate ions in acidic aqueous solution.

BrO3- (aq) + 5 Br- (aq) + 6 H+ (aq)   →   3 Br2 (aq) + 3 H2O (l)

Your objectives are

You have access to solid potassium bromide and potassium bromate and a concentrated perchloric acid solution as well as a stopped-flow apparatus. You must decide how to prepare the solutions used in the experiment and how to perform the stopped-flow experiment. (There are some restrictions on the concentrations that can be used.)

The spectrophotometer has been set to the absorbance maximum of bromine, which is the only colored species in this chemical system. The experimental data is a plot of absorbance vs time. You may need to find a way to convert the absorbance data into concentration data for bromine and/or other species. The uncertainty in the spectrophotometric measurements makes both very small and very large absorbances unreliable. The optimal operating range is absorbances between 0.1 and 1.0, though absorbances down to 0.01 and as high as 1.5 usually do not involve excessive error.

You may use any technique or strategy for achieving the experimental objectives. Any pair of values may be plotted on the graph at the left; linear regression may be performed on the data set.

Solution in Top Syringe
[BrO3-]: mole/L
[H+]: mole/L
Volume Delivered: mL

Solution in Bottom Syringe
[Br-]: mole/L
[H+]: mole/L
Volume Delivered: mL

Final Time: sec
Time Increment: sec

Kinetic Plots
A vs t     ln[Af-A] vs t     1/(Af-A) vs t

slope:         intercept:  
Data Points
x y





Isolation Method

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