Question

CFCs splits up in stratosphere to release chlorine by the action of
A. UV-A
B. UV-B
C. UV-C
D. All of the above

Answer 1

Hint: In the stratosphere the ozone is the deep layer. The layer covers the entire earth from harmful ultraviolet radiation that comes from the sun.

Complete Answer:
- Ozone is present in the stratosphere part of the atmosphere. Bad ozone is found in the lower atmosphere which is called the troposphere whereas good ozone is found in stratosphere which form a shield to absorb the UV rays from the sun.
- The high energy ultraviolet radiation splits ozone into molecular and atomic oxygen with large amounts of heat . CFCs move upward and reach the stratosphere. UV rays act on them releasing Cl atoms.
- In presence of Cl ozone degrades releasing molecular oxygen.
- Ozone depletion is the reduction of concentration of the ozone layer. It is formed due to an increased concentration of ozone depleting substances such asCFCs . Methyl bromide, chlorine, nitrogen oxide etc in the atmosphere.
- Chlorine is widely used in refrigerators. The CFCs magnate from the troposphere to the stratosphere where they release chlorine atoms by the action of UV rays on them.
- The release of chlorine atoms causes the conversion of ozone to the molecular oxygen 10,000 molecules of ozone can be destroyed by one atom of chlorine and causes ozone depletion.

Note: The Montreal Protocol was signed to control the emission of ozone depleting substances.
- The formation of ozone holes occurs due to increased concentration of UV-B radiation on the surface of the earth. UV-B damages DNA and activates the process of skin ageing.