Tiêu đề DPP 6 Solutions.pdf ✅

Class : XIth Subject : CHEMISTRY Date : DPP No. : 6 4 (d) Classical or London type smog is formed by the combination of soot particles with oxides of sulphur while climate is cool and humid. Due to presence of soot and oxides of sulphur, it is reducing in nature. Photochemical smog or Los Angeles smog is obtained from nitrogen oxides when climate is warm, dry and sunny. Due to presence of O3 and NO2 (strong oxidising agents), it is oxidising in nature. CO does not play any role in the formation of photochemical smog 5 (a) Pneumoconiosis is caused by in halation of coal dust 6 (c) Detergents and fertilizers contain phosphates as additives. The addition of phosphorous to water, in the form of the phosphate anion (PO 3― 4 ), encourages the formation of algae, which reduces the dissolved oxygen concentration of water. This process is known as eutrophication. 8 (c) BOD5 means, dissolved oxygen consumed in five days 9 (d) During the formation of photochemical smog the level of ozone in the atmosphere goes down. NO + O3 hv NO2 + O2 In the atmosphere the organic compounds rapidly react with O3,NO2 to form other noxious photochemical products known as peroxyacyl nitrates (PANs) and acrolein. Photochemical smog occurs in warm, dry and sunny climate, generally during the day time while classical smog occurs in cool humid climate, generally in the early morning hours of winter months. 10 (a) Methyl isocyanate (MIC) gas was released during Bhopal tragedy 11 (c) Mesosphere and thermosphere are collectively known as ionosphere as in these, gases are present in their ionised form Topic :- Environmental Chemistry Solutions
14 (b) Photochemical smog is initiated by the photochemical dissociation of NO2 and the resulting secondary reactions involving unsaturated hydrocarbons, other organic compounds and free radicals, lead to the formation of organic peroxides and ozone. NO2(g) UV light NO(g) +[O] O2(g) +[O]→O3(g) O3 +NO →NO2 + O2 Brown gas (In high concentration Forms haze) Hydrocarbons + O3,O2,O,NO2,NO peroxides, peroxyacetyl nitrate, formaldehyde, ozone aldehyde, acrolein, etc. oxidised hydrocarbons and ozone in the presence of humidity cause photochemical smog, which dissipates at night. 17 (a) Nitrogen gas is present in air up to 78% by volume. It does not cause pollution.
ANSWER-KEY Q. 1 2 3 4 5 6 7 8 9 10 A. A D B D A C D C D A Q. 11 12 13 14 15 16 17 18 19 20 A. C B C B A D A B B D