Question

Acid rain is caused by an increase in the atmospheric concentration of?

• A. O₃ and dust
• B. SO₂ and NO₂
• C. SO₃ and CO
• D. CO₂ and CO

Answer 1

The correct option is B

SO₂ and NO₂

The correct option is B.

Explanation of correct option:

1. Acid rain refers to rainfall with a pH of less than 5.
2. Increased concentrations of sulfur dioxide (SO₂) and nitrogen oxides (NO₂) are the primary causes of acid rain.
3. These gases are emitted from industries, thermal power plants, and automobiles.
4. SO₂ and NO₂ are changed into acids (H₂SO₄ and HNO₃) when they combine with oxygen and water.

Explanation of incorrect option:

Option A:

1. Ozone (O₃) present in the stratosphere prevents harmful UV rays from reaching the earth’s surface.
2. Dust particles are a major source of air pollution.

Option C:

1. Sulfur trioxide (SO₃ ) and carbon monoxide (CO) are responsible for air pollution.
2. They cause respiratory illness in humans.

Option D:

1. Cabon dioxide (CO₂) is a major greenhouse gas that is responsible for global warming.
2. CO is an air pollutant produced by the incomplete combustion of fossil fuels. It is also released by automobile exhaust.

Final answer: Acid rain is caused by an increase in the atmospheric concentration of SO₂ and NO₂.