Final answer:
Acid rain is characterized by having a pH less than 5 and is formed when nonmetal oxides react with water in the atmosphere, resulting in more acidic compounds like sulfuric acid and nitric acid. This can have harmful effects on the environment and is largely caused by emissions from the burning of fossil fuels.
Step-by-step explanation:
Understanding Acid Rain
Acid rain (or snow) occurs when the pH of precipitation is less than 5.6. Normal rainwater typically has a pH between 5 and 6 due to carbon dioxide dissolving and forming weak carbonic acid. Acid rain, however, contains more acidic compounds like sulfuric acid and nitric acid, resulting from the reaction of water with various nonmetal oxides like CO2, SO2, SO3, NO, and NO2. These oxides can come from natural sources such as volcanoes and decaying vegetation, or from anthropogenic activities, particularly the combustion of fossil fuels, which release sulfur dioxide and nitrogen oxides into the atmosphere. When these gases react with water, they form acidic compounds that result in precipitation with a pH of less than 5—making it more corrosive and harmful to the environment and living organisms.
Acid rain can have detrimental effects on ecosystems, damaging forests, lakes, and soils. It can kill insects, aquatic life, and plants by altering the pH balance of habitats essential for their survival. This type of pollution is a global problem, requiring attention and measures to reduce the emissions of the precursor gases leading to acid rain formation.