A factory was started near a village. Suddenly villagers started feeling the presence of irriting vapour in the village and cases of headache, chest pain, cough, dryness of throat and breathing problems increased. Villagers blamed the emissions from the chimney of the factory for such problems. Explain what colud have happend. Give chemical reactions for the support of your explanation.

Explanation

The symptoms observed in villagers show the presence of oxides of nitrogen and sulphur in the environment. These must be coming out of the chimney of the factory. This is due to the combustion of fossil fuels such as coal, oil, natural gas, gasoline etc., to produce high temperature at which oxidation of atmospheric nitrogen takes place forming nitric oxide (NO) and nitrogen dioxide `(NO_2)` as:
`N_2+O_2 overset(1200-1750^(@)C)iff 2NO`
`2NO+O_2 overset(1100^(@)C)iff 2NO_2`
The sulphur present in coal and fuel oil on combustion gives `SO_2` Sulphur dioxide is also produced by the roasting of sulphide ores such as copper pyrite `(CuFeS_2)`, iron pyrite `(FeS_2)`, copper glance `(Cu_2S)` etc.
`Cu_2S+ O_2 to 2Cu+SO_2`
`2FeS_2 + 5O_2 to FeO + 4SO_2 `