Some time ago formation of polar stratospheri clouds reported over Antarctica. Why were these formed ? What happens when such clouds break up by warmth of sunlight ?

Some time ago formation of polar stratospheric clouds reported over Antarctica. Why were these formed ? What happens when such clouds break up by warmth of sunlight ?

Mention the causes for formation of polar stratospheric clouds over Antarctica ? What happens when such clouds break up in presence of sunlight?

Ozone layer acts as one of the most important life support system. The major cause of ozone layer destruction is believed to be the release of chlorofluorocarbon compounds. UV radiation causes the chlorofluouocarbons to dissociate : CF_(2) Cl overset(hv)(rarr) Cl* +CF_(2) CI A highly reactive chlorine atomis responsible for the decomposition of ozone. Cl* + O_(3) (g) rarr ClO* + O_(2) (g) ClO* + O(g) rarr Cl* + O_(2) (g) Free radicals of chlorine decompose ozone molecules in a chain reaction. The depletion of ozone layer leading to ozone hole has, however, been mainly observed in the stratosphere over Antarctica. Special type of cloud called polar stratospheric colouds are formed over Antarctica.These clouds (contain solid HNO_(3).3H_(2)O ) play an important role in ozone depletion. ClO* + NO_(2) rarr ClONO_(2) ClONO_(2) + H_(2) O rarr HOCl + HNO_(3) ClONO_(2) + HCl rarr Cl_(2) + HNO_(3) HOCl overset(hv)(rarr) HO* + Cl* The reactive chlorine atoms thus formed are rendered to deplete ozone layer. The ozone layer is present in :

Ozone layer acts as one of the most important life support system. The major cause of ozone layer destruction is believed to be the release of chlorofluorocarbon compounds. UV radiation causes the chlorofluouocarbons to dissociate : CF_(2) Cl overset(hv)(rarr) Cl* +CF_(2) CI A highly reactive chlorine atomis responsible for the decomposition of ozone. Cl* + O_(3) (g) rarr ClO* + O_(2) (g) ClO* + O(g) rarr Cl* + O_(2) (g) Free radicals of chlorine decompose ozone molecules in a chain reaction. The depletion of ozone layer leading to ozone hole has, however, been mainly observed in the stratosphere over Antarctica. Special type of cloud called polar stratospheric colouds are formed over Antarctica.These clouds (contain solid HNO_(3).3H_(2)O ) play an important role in ozone depletion. ClO* + NO_(2) rarr ClONO_(2) ClONO_(2) + H_(2) O rarr HOCl + HNO_(3) ClONO_(2) + HCl rarr Cl_(2) + HNO_(3) HOCl overset(hv)(rarr) HO* + Cl* The reactive chlorine atoms thus formed are rendered to deplete ozone layer. Peeling of ozone umbrella, which protects us from UV rays is caused by: