Acid rain has a pH lower than normal rain due to emissions of which compounds?

Acid rain has a pH lower than normal rain due to emissions of which compounds?

• A. Nitrogen compounds
• B. Carbon dioxide
• C. Oxygen
• D. Sulfur compounds

Answer: (D)

Acid rain becomes more acidic because pollutants released into the atmosphere react with rainwater to form strong acids. Sulfur compounds, especially sulfur dioxide (SO2) and sulfur trioxide (SO3) from burning fossil fuels, dissolve in cloud droplets and react to produce sulfurous acid (H2SO3) and sulfuric acid (H2SO4). Sulfuric acid dissociates readily to release hydrogen ions, which increases the acidity and lowers the pH of rain. While carbon dioxide also makes rain slightly acidic by forming carbonic acid, its effect is much weaker. Nitrogen compounds can contribute as well, but sulfur compounds are the primary driver described here, making them the best explanation for rain with a pH lower than normal.

Acid rain becomes more acidic because pollutants released into the atmosphere react with rainwater to form strong acids. Sulfur compounds, especially sulfur dioxide (SO2) and sulfur trioxide (SO3) from burning fossil fuels, dissolve in cloud droplets and react to produce sulfurous acid (H2SO3) and sulfuric acid (H2SO4). Sulfuric acid dissociates readily to release hydrogen ions, which increases the acidity and lowers the pH of rain. While carbon dioxide also makes rain slightly acidic by forming carbonic acid, its effect is much weaker. Nitrogen compounds can contribute as well, but sulfur compounds are the primary driver described here, making them the best explanation for rain with a pH lower than normal.