First, a high school student should exercise extreme caution in experimenting with the generation of ozone - this is a TOXIC gas, and should only be generated under carefully controlled conditions. Ozone can be detected with a spectrophotometer by observing its absorbance at 260 nm (254 nm from a low pressure mercury lamp will do). It can also be detected by bubbling the gas through a concentrated solution of KI (Potassium Iodide). This generates the triiodide ion, which can be detected at 352 nm by a spectrophotometer.
Ozone (O3) does not react directly with CFCs. CFCs bring about a depletion of ozone in the upper atmosphere by a mechanism that starts with the photodissociation of CFC's (by the far UV rays of the Sun) in the upper atmosphere. This generates free chlorine atoms that then react with ozone in a chain reaction culminating in its conversion to oxygen (O2).
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