Which emissions contribute to acid rain by transforming into sulfuric and nitric acids in the atmosphere?

• A. CO2 and CH4
• B. SO2 and NOx
• C. O2 and N2
• D. O3 and CO

Answer: (B)

Acid rain mainly forms when sulfur and nitrogen gases released from burning fossil fuels are transformed in the atmosphere into sulfuric acid and nitric acid. Sulfur dioxide (SO2) oxidizes and reacts in cloud droplets to become sulfuric acid (H2SO4), while nitrogen oxides (NOx) do the same to form nitric acid (HNO3). These acids then dissolve in rain, making it acidic.

That’s why the emissions that contribute to acid rain are SO2 and NOx. Other options involve gases like CO2, CH4, O2, N2, O3, and CO, which aren’t the primary precursors to sulfuric and nitric acids in rain; they may affect air chemistry in other ways, but they don’t directly generate the acids responsible for acid rain.