Given below are two statements, one is labelled as Assertion (A) and the other as Reason (R).

Assertion (A): CO2, SO2 and NO2 gases get dissolved in rain water and produce acid rain.

Reason (R): Atmospheric air is polluted due to high concentration of gases like carbon dioxide, sulphur dioxide and oxides of nitrogen.

Select the correct answer from the codes given below:

The correct answer is Option 3

Key Points

• Both (A) and (R) are true and (R) is the correct explanation of (A).

• Assertion (A): CO₂, SO₂, and NO₂ gases get dissolved in rainwater and produce acid rain.

  • True. These gases react with water vapor in the atmosphere to form acids:
  • CO₂ (Carbon Dioxide) + H₂O → H₂CO₃ (Carbonic Acid)
  • SO₂ (Sulfur Dioxide) + H₂O → H₂SO₃ (Sulfurous Acid) (which can further oxidize to H₂SO₄ - Sulfuric Acid)
  • NO₂ (Nitrogen Dioxide) + H₂O → HNO₃ (Nitric Acid)
• These acids mix with rainwater, leading to acid rain, which harms soil, water bodies, and infrastructure.
• Reason (R): Atmospheric air is polluted due to high concentration of gases like CO₂, SO₂, and NO₂.
  • True. These gases are primarily released from sources like burning fossil fuels (coal, oil, and gas), industrial emissions, and vehicle exhausts, contributing to air pollution and ultimately leading to acid rain.
  • Since Reason (R) correctly explains Assertion (A), the correct choice is:
• Hence, Both (A) and (R) are true, and (R) is the correct explanation of (A).