Acid rain is primarily due to _________.

Key Points

Explanation:

• Normal rain has a pH of about 5.6; it is slightly acidic because carbon dioxide (CO2) dissolves into it forming weak carbonic acid. 
• Acid rain usually has a pH between 4.2 and 4.4.
• Acid rain, or acid deposition, is a broad term that includes any form of precipitation with acidic components. such as sulfuric or nitric acid that falls to the ground from the atmosphere in wet or dry forms. 
• This can include rain, snow, fog, hail or even dust that is acidic.
• Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOX) are emitted into the atmosphere and transported by wind and air currents.
• The SO2 and NOX react with water, oxygen, and other chemicals to form sulfuric and nitric acids. 

SO₂ + H2O → H₂SO₃

• These then mix with water and other materials before falling to the ground.