please explain the mechanism of ozone depletion(by chlorofluorocarbons) step by step with reactions

Asked by kanwal sandhu | 21st Jan, 2012, 08:37: PM

Expert Answer:

A relatively recent concern is the depletion of ozone, O3 due to the presence of chlorine in the troposphere, and eventually their migration to the stratosphere. A major source of chlorine is Freons: CFCl3 (Freon 11), CF2Cl2 (Freon 12), C2F3Cl3 (Freon 113), C2F4Cl2 (Freon 114). Freons decompose in the troposphere. For example,CFCl3 ® CFCl2 + Cl
CF2Cl3 ® CF2Cl + Cl.
The chlorine atoms catalyze the decomposition of ozone,


Cl + O3 ® ClO + O2and ClO molecules further react with O generated due to photochemical decomposition of ozone:


O3 + h v ® O + O2,
ClO + O ® Cl + O2
O + O3 ® O2 + O2.
The net result or reaction is
2 O3 ® 3 O2

Answered by  | 22nd Jan, 2012, 10:29: AM

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