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1PU CHEMISTRY ENVIRONMENTAL CHEMISTRY (1 ENVIRONMENTAL CHEMISTR) ONE MARK QUESTION 1. Define the terms atmosphere,biosphere? A) Atmosphere :- Atmosphere is the protective blanket of gases surrounding the earth. Biosphere :- All living species inclading human beings and animals constitute Biosphere, 2) Explain the terms Lithosphere,Hydrophere? : A) Lithosphere :- Lithosphere is the outer mantle of the solid earth consisting of minerals and the soil. Hydrosphere :- All the natural water resources together constitude the hydrosphere.These include Oceans, seas, rivers, lakes, streams, reser voirs, glaciers, etc. 3) Define the term soil Pollution? . A) Soil Pollution :- The pollution due to industrial wastes,urban wastes,radioactive pollutants.agricultural practices,chemical and mechanical pollutants,biological agents,soil sedi- ments etc is called soil pollution. 4) What is chemical oxygen demand (COD)? A) The amount of oxygen required to oxidise organic substances present in po as chemical oxygen demand. It is an important parameter for determining the quality of water. 5 What is Bio chemical oxygen demand ( BOD) ? A) The amount of oxygen used by the suitable micro-organisms present in water during five days at 20%C is called biochemical oxygen demand. * For pure water, BOD is about 1 ppm BOD greater than 17ppmindicates is harmful. 6) What are Troposphere and Stratosphere? A) Troposphere :- The lowest region of atmosphere in which the human beings along with other organisms live is called troposphere.It extends upto height of 10km from sea level. Stratosphere :- The region ofatmosphere lying between 10 and 50 km above sea level is called as stratosphere. It contains dinitrogen,dioxygen,ozone and little water vapour. 7 Name-the major Particulate pollutants present in troposphere? A) Troposphere contains gaseous and particulate pollutants. The major particulate pollutants are dust,mist,fumes,smoke,smog,etc. ' 8) Give the possible BOD values of clean water and the polluted water ? A) The BOD value for clean water is about 1ppm. The BOD value for polluted water is about 100 - 4000 ppm 9 What agrochemicals are responsible for water pollution ? , A) Sodium chlorate, Sodium arsinate,Aldrin Dieldrin.etc..are responsible for water pollution. , 10) — Listout four gaseous pollutants present in Troposphere? á A) Troposphere contains both gaseous and particulate pollutants.The major gaseous pollutants are oxides of sulphur,nitrogen,carbon,hydrogen sulphide,hydro carbons,ozone and other oxidants. 11. What are biodegradable and nof-biodegradable pollutants? s Ans : For answer, consult section 14.1. 12. What are the sources of dissolved oxygen in water? E Ans : In water, the source of oxygen is either atmospheric oxygen or photosynthesis carried in plants during day light. E 13. — Whatis thc importance of measuring BOD of a water body ? Ans : B.O.D. ¡.e. biological oxygen demand is a measure level of pollution caused by organic biodegrad- able material in water, In case B.O.D. level is low, this means that water contains less of organic material in it. TWO MARKS QUESTIONS 14) Name two adverse effects caused by acid rains? A) The adverse effects caused by acid rain are. lluted water is called high pollution and y NARAYANA STUDY MATERIAL TPU CHEMISTRY A) 16) A) 17) A) 18) A) 19 20) A) NARAJANA STUDY MATERIAL a ENVIRONM ENTAL CHEMISTRY 0 Sa rain washes a way nutrients needed for their growth. (1 ss rain causes respiratory ailments in human beings and animals. s (id) It corrodes water pipes resulting in leaching of heavy metals like iron. 15) What is classical smog?and what is its chemical character (oxidixing,seducing) ? Classical smog is a mixture of smoke, fog and sulphur dioxide.JL OCcurs in cool humid climate. Photochemical smog has high e dd hence called oxidising smog tion of oxidising agents an: so called as reducing smog. Name the common components of photchemical smog? ques The common components of photochemical smog are Ozone,nitric Oxide,acrolein,Formal dehyde and peroxyacetyl nitrate, (PAN ). : A It causes serious health problems.Both ozone and PAN act as powerful eye irritants. What is PAN ? what effect is caused by it ? Na PAN is peroxyacetyl nitrate. Ozone reacts with unburnt hydrocarbons in the polluted air in the presence of strong oxidising agents like NO, to produce chemicals such as formaldehyde,acrolein and PAN. while it is a reducing mixture,so ii 3CH, +20, >3CH, =0+3H,0 CH, =CHCH CH,COONO, Acrolein — * Il PAN -0 PAN act as powerful eye irritants. Give the chemical equations involved in the ozone depletion by CFCL ? Chlorofluorocarbons released in to atmosphere mix with atmospheric gases and reach the stratosphere.There,they get broken down by powerful uv radiations,releasing chlorine free radical. CF Cl) 25 CT" + CC" F¿Cl CECL The chlorine radical reacts with O, to form chlorine monoxide radicals and oxygen. el+o, > clor+o, chlorine monoxide radical reacts with atomic oxygen produces more chlorine radicals. clo" +0>cl +0, The chlorine radiacals are continuously regenerated and cause ozone depletion. What is ozone hole? where was it first observed? Depletión of ozone layer commonly known as ozone hole.. Chlorofluorocarbons released in to atmosphere mix with atmospheric gases and reach the stratosphere.There,they get broken down by powerful uv radiations,releasing chlorine free radical. z CFCL, 2501 +C"F,Cl The chlorine radical reacts with O, to form chlorine monoxide radicals and oxygen. CF +0, +CIO"+0, chloriñe monoxide radical reacts with atomic oxygeri produces more chlorine radicals. CIO" +0 >CT +0, . The chlorine radiacals are continuously regenerated and cause ozone depletion. In summer season NO, and CH, react with chlorine monoxide and chlorine atoms forming chlorine sinks prevent ozone depletion. Ozone hole was observed over the south pole. Define the terms Sink,COD,BOD and TLV. Sink :- The medium which retains and interacts with a long lived pollutant is called the Sink. ( Oceans are sinks for atmospheric Carbon Dioxide). Threshold limit value (TLV) :- The permisible level of toxic pollutant in the atmosphere to Page No: 229 IPU CHEMISTRY : ENVIRONMENTAL CHEMISTRY 28. result. oxygen content ofwater decreases, This leads to anaerobic conditions resulting in the death or ; animals and also inhibits the growth ofother water animals, Since vxygen is very essential for animal life, in its absence, there is decay and death ofanimals leading to stinking and foul smell. Why does water covered with excessive algae growili become pollated? Ans : For answer consult Q, No 7 29. Ans: Áns : 31. A factory Was started near a village, Suddeniy villagers started fecling the ls ES tating vapours in the village und cases of hendache, chest pain, cough, pi » Ene ñ breathing problems inercased. Villagers blamed the emissions from the chimney o % e A factory for such problems. Explain what could have happened. Give a a the support of your explanation. + i The available information suggests that cóal contamináted with sulphur was e a fuel. Sulphur got oxidised to both SO, aud SO, . > S(5)+0,(8)—> SO, (g) :so.(g)+30:(8) —>50,(8) The oxidation of sulphur dioxide into sulphur trioxide is enhanced by the particulate matter. Bot. these gases are extremely poisonous and irritating. They"cause all those problems that tere experi enced by the villagers. Oxidation of sulphur dioxide into sulphur trioxide in the absence of a catalyst is a slow process but this oxidation occurs easily in the atmosphere. Explain how does this happen. Give chemical reaction for the convrsion of SO, into SO, ? Sulphur dioxide (SO, ) is normally oxidised to :sulphur vioxide (SQ,) in the presence of a catalyst. However, particulate matter present.in the atmosphete promotes the oxidation of sulphur dioxide. Even ozone layer in the atmosphere causes the oxidation. ed 50. (3)+0,(2)—>50,(8)+0, (3) From where does ozone come in the photochemical smog? Ans : Oxygen atoms released from nitrogen perdioxide during its photochemical decomposition com- bine with oxygen to form ozone. NO, (2) —>5NO(g)+0(8). 0.(2)+0(2)—>0,(8) MORE THAN 4 MARKS : . A 32) List out the industrial wastes that cause water pollution and what are the international standards fixed for drinking water ? A) NARAYANA STUDY MATERIAL The international Standards for drinking water are given below and they must be followed. Fluoride : - For drinking purpose ,water should be tested for fluoride ion concentration. lts defi ciency in drinking water is harmful to man and causes diseases such as tooth decay etc.Soluble fluride is often added to drinking water to bring its concentration upto |: ppm or 1 mg dm Lead :- Drinking water gets contaminated with lead when lead pi water. a . Sulphate :- Exvessive sulphate ( >500 ppm) in drinking water e. moderate levels it it harmless. ; Nitrate :- The maximum limit of nitrate in drinking water is 50 ppm. Excess nitrate in drinking water 4 5 can cause disease such as methemoglobinemía ( *blue baby'syndrome. ) Industrial A z ter . trial solid wastes are also sorted out as biogradable and non-degradable Mo pes are used for transportation of uses laxative effect,otherwise at Page No: 231 TPU CHEMISTRY 34) A) ENVIRONMENTAL CHEMISTRY wastes.Biodgradable wastes are generated by cotton mills and textiles factories. Non-biodegradable wastes are generated by thermal power plants which produce fly ash; integrated iron and stecl plants whichproduce blast furnace slag and steel melting slag. Industries manuficcturing aluminium,zine and copper produce mud and tailings. Fertilizer indus tries produce gypsum, Hazardous wastes s uch as inflammables,composite explosives or highly *. reactive substances are produced by industries dealing in metals,chemicals,drugs,pharms- z ceuticals, dyes,pesticides.rubber goods ete. What is environmental pollution ? How many types of py Environmental polution is the effect of undesirable changes effects on plants,animals and human beings.Pollutions can be solid liquid ation than in natural abundance and aré produced due to human activi- oltution are encountered ?. in our surroundings that have harmful. or gaseous substances present in greater concentr ties or due to natural bappenings, Pollutants which arc slowly degradable remain in the environment in an unchanged form for many decades.For example, substances such as dichlorodiphenyltri chloroethane (DDT), plastic materials,heavy metals ,manychemicals, nuclear wastes etc...once realeased into the environmentare difficult to be removed. These pollutions cannot be degraded by natural processes and are harmíul to living organisms.In the process of environmental pollution,pollutants originate from a source and get transported by air or water or are dumped into the soil. Types of pollutions :- In addition to material pollutants,we have noise,electroma; pollutants.The pollution may be natural or artificial ¡.e.,due to activities of man. It is better to classify pollution either according to the environment in which it occurs (air,water,soil or land,noise etc.) or accordingto the pollutants by which the pollu tion occurs. We will study here the classification of pollution according to the environment in which it occurs i.e.as water,soil or air pollution. Explain the following in detail. a) global warming b) ozone depletion €) Acid rain 4) global wvarming :- Green house effect or Global warming :- The temperature of the earth's surface is maintained by the energy balance of the sun's'rays that strike the 'éarth and the heart that is radiated back by the earth into the outer space.About 75% of the solar energy reaching the earth is absorbed by the earth's surface and the remaining heat rediates the atmosphere.Some of the heart is trapped by CO,,CH,,0,,CCl,F, etc. gasesand water vapour.They add to heat, the atmosphere causing global warming.This phenomenon is called the natural green house effect. Because of more energy radiated back to the earth by the above gases due to their, increased concentration and their blanketing effect,the temperature of the earth increases.This phenomenon is known as global warming or green house effect. Higher the concentrations of these gases in the atmosphere more ¡s the infra-red radiation trapped by these gases which is reflected back to the earth's surface and more is the global warming. b)Ozone depletion :- In stratosphere ,they get broken down by powerful UV radiations,releasing chlorine free radical. p CECI, (2) 5Cr (2)+ CF.CI(g) O) The chlorine radical then reacts with stratospheric ozone to form chlorine “monoxide radicals and ¡gnetic.as d) Eutrophication molecular oxygen, Cr (8)+0,(g) >C10' (8)+0, (2) (ii Reaction of ehlorine monoxide radical atomic oxygen produces more chlorine radicals CIO (g)+0(g) >C1 (8)+0, (2) (iii) The chlorine radicals are continuously regenerated and cause the breakdovm of Ozone. with the depletion of ozone layer,more UV radiation filters into troposphere radiations lead to ageing of skin ,cataract,sunburn,skin cancer,killing of many phytoplanktons,damage to fish productivity.etc. It has also been reported that plantproteins get easily affected by UY radiations NARAYANA STUDY MATERIAL z Page No: 232 I PU CHEMISTRY. - : . . ENVIRONMENTALCHEMISTRy suggest that instead of using conventional fuels and energy systems, non conventional fuels and non- conventional energy systems must be put into practice.Because of this,pollution would be reduced, During a synthesis, the selected starting materials should be converted into products by 100%. This is possible if: some optimum cónditions of synthesis are brought in.For example, compared to organic solvents thé aqueous mediumis more safe because ofthe high specific heat. low volatility,non-inflammab;. “ ityandno carcinogenic effects of water. Green chemistry is cost effective approach that involves mini- mum chemical usage, minimum energy consumption and minimum waste (pollutant) generation. 
