MCQ Detailed View

Acid rain is a form of precipitation that has unusually high acidity (low pH) due to the presence of certain chemical pollutants in the atmosphere. The main cause of acid rain is the emission of Sulfur Dioxide (SO₂) and Nitrogen Oxides (NOₓ), which are released from various natural and human activities. When these gases mix with water vapor and oxygen in the atmosphere, they undergo chemical reactions to form sulfuric acid (H₂SO₄) and nitric acid (HNO₃). These acids then fall to the ground in the form of acid rain, fog, or snow.

Sources of Sulfur Dioxide and Nitrogen Oxides:

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   Burning of Fossil Fuels:

   
   
   
   
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     Power plants, industrial factories, and vehicles emit large amounts of SO₂ and NOₓ by burning coal, oil, and natural gas.

     
     
   
   
   
   


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   Volcanic Eruptions:

   
   
   
   
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     Natural events releasing sulfur gases into the atmosphere.

     
     
   
   
   
   


3. 
   

   Agricultural Activities:

   
   
   
   
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     Fertilizer use can indirectly release nitrogen oxides.

     
     
   
   
   
   

Effects of Acid Rain:

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  Damage to Vegetation: Acid rain leaches nutrients from soil, damaging plants and forests.

  
  


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  Water Pollution: Lowers pH of lakes and rivers, harming aquatic life.

  
  


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  Corrosion of Buildings: Especially harmful to structures made of limestone and marble.

  
  


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  Human Health Risks: Contributes to respiratory problems when acidic gases are inhaled.

  
  

Why Other Options Are Incorrect:

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  Potassium Nitrate: While nitrates exist in the environment, they are not the main gaseous pollutants causing acid rain.

  
  


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  Charcoal and Sulfur: Incomplete terms that do not represent actual acid rain chemistry.

  
  

Thus, the correct answer is Option D: Sulfur Dioxide and Nitrogen Oxide, as these two emissions are the primary contributors to acid precipitation worldwide.