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ICSE Class 9 Chemistry Question 26 of 31

Atmospheric Pollution — Question 12

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12
Question

Question 2(iv)

Assertion (A): Photochemical smog is composed of oxides of nitrogen, ozone, peroxyacetyl nitrates and other organic compounds.

Reason (R): Photochemical smog is formed by the interaction of certain pollutants in cold weather conditions.

  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
Answer

A is true but R is false.

Explanation— Photochemical smog is a type of air pollution formed when sunlight reacts with pollutants like nitrogen oxides Ozone (O3), Peroxyacetyl nitrate (PAN), Nitrogen oxides (NO and NO2) and Other oxidants and organic compounds. Hence, the assertion (A) is true.

Photochemical smog forms primarily in warm, sunny conditions, not cold weather. Hence, the reason (R) is false.