Question 11A.27: (a) Suggest a quantitative method for estimation of the gas ......
(a) Suggest a quantitative method for estimation of the gas which protects us from U.V. rays of the sun.
(b) Nitrogen oxides emitted from the exhaust system of supersonic jet aeroplanes slowly deplete the concentration of ozone layer in upper atmosphere. Comment.
(a) The gas which protects us from U.V. rays of the sun is ozone. It reacts with I^- ions to give iodine as :
O _3+2 I ^{-}+ H _2 O \longrightarrow O _2+ I _2+2 OH ^{-}
I_2 liberated is titrated against sodium thiosulphate solution and amount of O_3 can be estimated.
(b) The release of nitrogen oxides (NO_x) into stratosphere by the exhaust system of supersonic jet aeroplanes deplete the concentration of O_3 because NO reacts with O_3 to give O_2.
NO (g)+ O _3(g) \longrightarrow NO _2(g)+ O _2(g)
Therefore, NO is slowly depleting the concentration of ozone.