Ozone Results
Creighton University
Part 2. Ozone + potassium indigo trisulfonate.





Here we can see the ozone discoloring the starch-iodide paper


This is our "reaction vessel".  We stopped the ozone generator every 1.0 minute by unplugging the power supply.  By then, 3.5 mL O2/O3 had been generated.  We vigorously shook the contents to assure all of the ozone had reacted with the PIT (potassium indigo trisulfonate) solution.  We know the exact molarity of the PIT solution, but do not know the exact reaction stoichiometry that takes place between PIT and O3.  

(Tere page 11) After each 1.0 minute, we measured the absorbance of the solution (and then returned the sample measured back to the reaction vessel).  The numerical results are:

...and they plot well.  The reaction seemed to speed up at the end and eventually the products became yellow.  At 11 minutes the solution looked green (Blue+Yellow) and at 12 minutes, it was only yellow.  An even straighter line could be obtained by stopping after 8 minutes.

We have determined that Pt and Pb give similar results.  What point of curiosity is that sometimes her generators make 4 mL/min and sometimes 7 mL per minute.