What acids are in acid rain?
Nitric acid and sulfuric acid
Acid rain occurs when pollutant gases like sulfur dioxide and nitrous oxides dissolve in water to form acids.
Sulfur dioxide is formed due to sulfur impurities in fuels (e.g. coal) being oxidised. Nitrous oxides are often formed in vehicle engines (e.g. cars). Nitrogen isn't usually reactive but in the extreme heat of an engine it oxidises (due to oxygen in the air) to form various oxides of nitrogen. These gases will then rise into the atmosphere and dissolve in rainwater to form acid rain.
Acid rain can cause all sorts of environmental issues - many ecosystems are sensitive to pH, especially marine ones so if acid rain falls into rivers or lakes it can damage the organisms living there. Trees are often damaged by acid rain, and soil can become too acidic for certain species of plant to grow (think in terms of enzymes being denatured by a pH that is too low or high).
Equally, buildings and statues made from calcium carbonate based rocks (commonly limestone) can be corroded as the calcium carbonate reacts with the acid in a neutralisation reaction to form a calcium salt, water and carbon dioxide.
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