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JEE Main · 2022 · 28 Jun 2022 · Shift 2 · Environmental Chemistry

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Correct statement about photo-chemical smog is :
  1. (A)It occurs in humid climate.
  2. (B)It is a mixture of smoke, fog and
  3. (C)It is reducing smog.
  4. (D)It results from reaction of unsaturated hydrocarbons.✓ Correct

Answer: (D)

Solution

Photochemical smog is formed by the action of sunlight on nitrogen oxides (NOₓ) and volatile organic compounds (VOCs), particularly unsaturated hydrocarbons, in the atmosphere. This produces secondary pollutants like ozone, PAN (peroxyacetyl nitrate), and aldehydes. It is an oxidizing smog (not reducing), occurs in warm, dry, sunny climates (not humid), and does not primarily involve SO₂ (which is characteristic of classical/London smog). Therefore, the correct statement is that it results from the reaction of unsaturated hydrocarbons.

JEE Main · 2022 · 28 Jun 2022 · Shift 2 · Single correct option

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