How did the depletion of ozone layer has created in the atmosphere over the Antarctica?Explain with reactions.

How did the depletion of ozone layer has created in the atmosphere ove

1.	How did the depletion of ozone layer has created in the atmosphere over the Antarctica?Explain with reactions.
Answer» Solution :In 1980s atmospheric scientists working in Antarctica reported about depletion of ozone layer commonly known as ozone hole. In summer season, NITROGEN dioxide and methane react with chlorine monoxide (reaction IV) and chlorine atoms (reaction V) forming chlorine SINKS. It preventing much ozone depletion. In winter, special type of clouds called polar STRATOSPHERIC clouds are formed over Antarctica. These clouds provide SURFACE on which chlorine nitrate formed (reaction IV) gets hydrolysed to form hypochlorous acid (reaction VI). It also reacts with hydrogen chloride a produced molecular chlorine. `Cloverset()O_((g)) + NO_(2(g)) to ClO NO_(2(g)) ""....(iv)` `overset()Cl_((g)) + CH_(4(g)) to overset()CH_(3(g)) + HCl_((g)) ""......(v)` `ClONO_(2(g)) + H_2 O_((g)) to HOCl_((g)) + HNO_(3(g)) "".....(vi)` `ClONO_(2(g)) + HCl_((g)) to Cl_(2(g)) + HNO_(3(g)) ""....(VII)` In spring, sunlight returns to the Antarctica. The sun.s warmth breaks up the could and HOCI and `Cl_2`are photolysed by sunlight, as given in reactions (viii) and (ix). `HOCl_((g)) overset(hv)to overset()OH_((g)) + overset()Cl_((g)) "".....(viii)` `Cl_(2(g)) overset(hv)to 2overset()Cl_((g))"".....(ix)` Thus, the chlorine radicals formed. It initiate the chain reaction for ozone depletion.