Information on an experiment on the production of ozone and its quantitative analysis
(If you are able to do that experiment for yourselves: Be careful: Some chemicals and the UV-light used in the experiment are harmful. Inform yourselve about the chemicals. Experiment carefully and protect yourselves!)
In a water-cooled immersion-lamp reactor an oxygen atmosphere with 40 mL potassium iodide solution (w=10%), 10 mL sulfuric acid (c=0,025 mol/L) and a few drops of starch solution on the bottom of the reactor is irradiated for 20 minutes. The solution must be stirred vigorously during irradiation. 20mL of the solution that has turned blue during illumination are first titrated with a sodium thiosulphate solution (c=0,001 mol/L) until it becomes colourless. Add bromothymol blue and titrate again, this time with sodium hydroxide solution (c=0,005 mol/L), until the colour turns blue again. In a few further measuring series you should add different gases (dichlorodifluoromethane, methane, nitrogen dioxide). Altogether results like the following can be obtained from the experiments:
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Figure 1: set-up for the production and quantitative determination of ozone.
© Tausch, von Wachtendonk: Chemie 2000+; Buchner Verlag, Bamberg 2001
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