7.2 Acid rain
The acidity of rainwater increases in polluted areas during thunderstorms e.g SO2 Sulphur dioxide from power plants during the combustion of fossil fuels and NO2 form automobiles. Exhaust fumes dissolve in rainwater producing acids. The pH of rainwater can be much lower due to the production of H2SO4 and HNO3 . By lightning during the thunderstorm. The rain may have a pH as low as 2. Acid Rain is defined as rain having a pH less than 5.
7.2.1 Role of nitric oxide and nitrogen dioxide in the formation of acid rain
Nitric oxide (NO) and nitrogen dioxide (NO2) play important roles in the formation of acid rain through both direct and catalytic processes. Here's an overview of their involvement:
7.2.2 Direct Role in Acid Rain Formation
Formation of Nitric Acid (HNO3)
Nitric oxide (NO) is initially produced during combustion processes, such as those occurring in vehicle engines and industrial activities. NO is relatively stable but can be oxidized to form NO2 :
Formation of Nitric Acid: NO2 can further react with hydroxyl radicals (OH) and water in the atmosphere to form nitric acid (HNO3) , a major component of acid rain:
Catalytic role in the oxidation of sulphur dioxide SO2 )