InterviewSolution
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InterviewSolution
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Write down the chemical equations of reaction involved during the formation of photochemical smog. How can it be controlled? |
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Answer» NO2 + UV radiation \(\overset{photolysis}{\rightarrow}\) NO + (O) ..................(i) O + O2 ⇌ O3 ............(ii) Ozone so formed oxidises NO to NO2 + O2 NO + O3 → NO2 + O2 ……(iii) (O) + Hydrocarbon → RCO \(\overset{O_2}{\rightarrow}\) RCO3 RCO3 + Hydrocarbons → CH2 = O, ketones, etc. RO3 + O2 → RCO2 + O3 RCO3 + NO → RCO2 + NO2 RCO3 + NO2 → RCO3NO2 (PAN) The presence of excessive O3, along with aldehydes ketones, PAN constitute photochemical smog. Control: (i) Efficient catalytic converters are being developed for fitting in the automobiles so that the emission of nitrogen oxides and hydrocarbons can be prevented. (ii) Certain chemical compounds are sprayed into atmosphere, which generate free radicals. These free radicals readily react with the free radicals responsible for the formation of photochemical smog and nullify their effect. (iii) Toxic nature causes coughing, wheezing, bronchial constrictions and irritation to respiratory mucous system. |
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