Acid rain causes erosion by chemically reacting with and dissolving certain minerals in rocks and buildings, effectively speeding up the weathering process.
Here's a breakdown of the process:
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Acid Rain Formation: Acid rain forms when pollutants like sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) are released into the atmosphere. These gases react with water, oxygen, and other chemicals to form sulfuric acid and nitric acid.
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Chemical Weathering: The acidic rainwater then comes into contact with surfaces like limestone, marble (which is primarily calcium carbonate), and sandstone.
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Dissolution Process: The acids in the rain react with the calcium carbonate in these rocks, causing it to dissolve. This reaction can be represented as follows:
CaCO₃ (Calcium Carbonate) + H₂SO₄ (Sulfuric Acid) → CaSO₄ (Calcium Sulfate) + H₂O (Water) + CO₂ (Carbon Dioxide)
The calcium sulfate is soluble in water and is washed away, leading to the gradual erosion of the rock.
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Impact on Structures: This process is particularly damaging to buildings, statues, and monuments made of limestone or marble, causing them to deteriorate over time.
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Examples of Affected Structures: The Taj Mahal in India and many historical buildings in Europe have been significantly impacted by acid rain.
In essence, acid rain enhances the natural weathering process by directly dissolving certain rock types, leading to their gradual erosion and disintegration.
