What is acid rain and what chemical reactions produce plant and material damage?

• A. Acid rain forms from sulfuric and nitric acids formed from SO2 and NOx; it lowers pH, dissolves nutrients, and damages leaves and buildings.
• B. Acid rain is rain that contains sugar; it improves plant growth.
• C. Acid rain forms from chlorine and ozone reactions.
• D. Acid rain only affects marine life.

Answer: (A)

Acid rain begins when gases released from burning fossil fuels, mainly sulfur dioxide and nitrogen oxides, react in the atmosphere to form sulfuric and nitric acids. These acids then mix with rain, dropping the pH well below normal rain. The acidic precipitation changes soil chemistry by increasing metal solubility and washing away essential nutrients, which reduces a plant’s ability to take up nutrients and can damage leaf tissue. For materials, acids react with substances like calcium carbonate in limestone and marble, slowly dissolving them and accelerating corrosion of buildings, statues, and sculptures. The idea that acid rain is just sugar-containing rain or is driven only by chlorine and ozone reactions isn’t accurate, and acid rain affects more than marine life—terrestrial plants and man-made surfaces are harmed too.