What is the primary cause of acid rain

Subject : Chemistry

Question: What is the primary cause of acid rain?

A. Methane emissions

B. Ozone layer depletion

C. Sulfur dioxide and nitrogen oxides emissions

D. Carbon dioxide emissions

Expert Verified Solution:

C. Sulfur dioxide and nitrogen oxides emissions – Sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) are the primary pollutants responsible for acid rain.

The correct answer is C. Sulfur dioxide and nitrogen oxides emissions.

Explanation:

Acid rain is a form of precipitation that contains high levels of sulfuric and nitric acids, making it more acidic than normal rain. The primary causes of acid rain are the emissions of sulfur dioxide (SO₂) and nitrogen oxides (NOₓ). These pollutants are released into the atmosphere through various human activities, including:

Burning of Fossil Fuels:

Power Plants and Factories: Combustion of coal and oil in power plants and industrial facilities emits significant amounts of SO₂ and NOₓ.

Vehicles: Emissions from cars, trucks, and other vehicles contribute to the release of nitrogen oxides.

Industrial Processes:

Certain manufacturing processes release sulfur dioxide and nitrogen oxides as byproducts.
Once released, these gases react with water vapor, oxygen, and other chemicals in the atmosphere to form sulfuric acid (H₂SO₄) and nitric acid (HNO₃). These acids then mix with precipitation, resulting in acid rain, which can have harmful effects on ecosystems, buildings, and human health.

Why Other Options Are Incorrect:

A. Methane emissions: Methane (CH₄) is a potent greenhouse gas contributing to global warming but does not directly cause acid rain.

B. Ozone layer depletion: This refers to the thinning of the ozone layer caused by chlorofluorocarbons (CFCs) and other ozone-depleting substances. It is a separate environmental issue from acid rain.

D. Carbon dioxide emissions: Carbon dioxide (CO₂) is the primary greenhouse gas responsible for climate change and global warming, not acid rain.