Question

Which of the following gases is primarily responsible for acid rain and photochemical smog?

• A. Carbon monoxide
• B. Ethylene
• C. Nitrogen oxides
• D. Methane

Answer 1

Answer:

C. Nitrogen oxides

• Correct Answer: Option C - Nitrogen oxides

• Nitrogen oxides (NOx) are primarily responsible for both acid rain and photochemical smog:

• Acid Rain: When nitrogen oxides are released into the atmosphere (primarily from vehicle emissions and power plants), they react with water, oxygen, and other chemicals to form nitric acid, which is a component of acid rain. While sulfur dioxide (SO2) also contributes significantly to acid rain by forming sulfuric acid, the question asks about gases responsible for BOTH acid rain AND photochemical smog.

• Photochemical Smog: Nitrogen oxides play a crucial role in photochemical smog formation. When NOx gases interact with volatile organic compounds (VOCs) in the presence of sunlight, they undergo a series of chemical reactions to produce ground-level ozone and other secondary pollutants that constitute photochemical smog.