What is the effect of chlorofluorocarbons?
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Chlorofluorocarbons (CFC) are a group of synthetic organic chemicals composed of carbon, oxygen, chlorine and fluorine. Two most common of these are CFC-11 and CFC-12 which are used as refrigerants, and as propellants in aerosol sprays. However, use of these chemicals is being stopped around the world because of their harmful effect on environment.
CFC CFC released from various source rise up in the atmosphere and there break down ozone molecules in the earth's upper atmosphere. This reduces the ability of the atmosphere to prevent too much of ultraviolet rays reaching the earth's surface. This in turn harms the animal and plant life on the earth.
These kinds of chemicals (often called CFCs) were a very hot topic in environmentalism about twenty years ago or so. They are no longer discussed much because we have moved on to things like greenhouse gasses.
CFCs came from things like refrigerators and aerosol cans. They were bad for the environment because they destroyed the ozone layer in the high atmosphere. The ozone layer protects the earth from many harmful parts of the sun's light. Most particularly, the ozone layer screens out much of the ultraviolet light before it enters the lower atmosphere.
Most CFCs were therefore banned in 1990.
Ozone protects us from the harmful UV radiations from the sun. It filters out all radiations below 3000A. Any depletion of ozone would, therefore, have catastrophic effects on life systems of the earth. Major pollutants responsible for this depletion are chlorofluorocarbons, nitrogen oxides and hydrocarbons.
CFCs are widely used as coolants in the air conditioners and refrigerators, cleaning solvents, aerosol propellants and in foam insulation. CFC is also used in fire extinguishing equipment. That escape as aerosol in the stratosphere.
Depletion of ozone in stratosphere causes direct as well as indirect harmful effects. Since the temperature rise in stratosphere is due to heat absorption by ozone, the reduction in ozone would lead to temperature changes and rainfall failures on earth.
Chlorofluorocarbons are compounds that were found in aerosol cans that propelled whatever was in the can out. It was found that these compounds were reactive with the ozone molecule in the atmosphere. They combined with the ozone because ozone could share the electrons in there molecules, hence depleting the ozone layer.
There is actually a thin layer of ozone in the stratosphere, which is about 20-50 kilometres above the Earth, and it acts like a shield, or a giant sunscreen, filtering out some of the harmful UV lights from the sun. Without ozone, the harmful radiation would reach the Earth's surface and there would be a drastic increase in people suffering from skin cancer, genetic mutations and eye damage, being it cataracts forming in the eye. It can also destroy marine life.
Scientists have discovered that the depletion of this majestic ozone layer is caused by chlorofluorocarbons or CFC for short, and they are compounds consisting of chlorine, carbon and fluorine. They were widely used as propellants for aerosols and as coolants in refrigerators and air-conditioners. They were also used in the manufacturing of packing foams.
In recent decades. large amounts of them are released into the atmosphere, and in the presence of sunlight, be decompose to form chlorine atoms. They react with ozone molecules in the stratosphere to form chlorine oxide and oxygen, thus destroying the ozone layer, and diffused through the air towards our world. If we don't stop the usage of these great tools of destruction, the world would cease as we know it and cause great catastrophe to mankind.
CFCs or chloro fluoro carbon are simply made of elements - carbon, fluorine and chlorine.
I have an example:
Freon : these are CFCS which are mainly derived from ethane and methane
it can be manufactured from CCl4 by swarts reaction(hallogen exchange reaction for fluorine)
3CCl4 + 2 SbF3-> 3 CCL2F2 + 2SbCl3
These compounds are very stable hence are not decomposed easily.
they react with ozone (O3) to give oxygen. hence they deplete ozone.
another such example
NO + O3 --> O2 + NO2
NO - Nitric oxide
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