If you don't know, you might be curious to know what CFC's are: they are responsible for the destruction of the ozone layer, the chlorofluorocarbons (CFC's) come from refrigeration systems, solvents, plastic foams, aerosol containers and many others. As the name implies, they consist of carbon (C), chlorine (Cl) and fluorine (F).
It is known that the ozone layer is a coating of ozone gas (O3) that surrounds the Earth, this layer has the function of protecting our planet, it works as a filter, that is, it filters a large part of the dangerous ultraviolet rays emitted by the Sun.
The ozone layer depletion process begins like this:
1. The CFC's, being light, reach higher altitudes (between 20 and 30 km) which corresponds to the Earth's stratosphere;
2. Upon reaching a certain altitude, CFC's are decomposed by ultraviolet radiation;
3. The decomposition of CFC's is a photolysis process and releases chlorine, fluorine and bromine atoms;
4. The catalytic reaction only occurs when chlorine atoms participate in cycles of reactions that deplete ozone. Catalysis Reaction Equations:
1st step: Cl + O3 → ClO + O2
2nd step: ClO + O → Cl + O2
3rd stage: The3 + O → 2 O2
Explaining: Did you notice that the catalytic reaction took place in three steps? In the first, the Chlorine atom breaks the O when it breaks off from the CFC's molecule3 forming ClO and O2. In the 2nd stage, chlorine is released from the oxygen and in the 3rd stage it starts to destroy the ozone, as shown in the equation.
These reactions were called catalytic because they function as catalysts, that is, they accelerate the destruction of the ozone layer. Chlorine is the main reactant in the reaction, it can destroy thousands of ozone molecules.
The increased incidence of skin cancer is linked to the action of ultraviolet rays, this is one of the consequences of the destruction of the ozone layer, another serious one is the greenhouse effect, responsible for the increase in temperature of the planet.
By Líria Alves
Graduated in Chemistry
See more!
How is the ozone layer destroyed?
Consequences of the destruction of the ozone layer
Source: Brazil School - https://brasilescola.uol.com.br/quimica/reacoes-cataliticas-os-cfcs.htm