Question

Identify the correct statements about photochemical smog
I. PAN is one of the components of photochemical smog
II. It forms cracks in rubber
III. It is an oxidizing smog

• A. I, II, III
• B. I, II only
• C. I, III only
• D. II, III only

Hint:

{Classical Smog (London Smog):} Cool, humid, $SO_2$ + particulates $\rightarrow$ Reducing. {Photochemical Smog (Los Angeles Smog):} Warm, sunny, $NO_x$ + Hydrocarbons $\rightarrow$ Oxidizing.

Answer 1

The Correct Option is A

Step 1: Analyze Photochemical Smog:
Photochemical smog occurs in warm, dry, and sunny climates due to the action of sunlight on unsaturated hydrocarbons and nitrogen oxides.
Step 2: Check Statements:

• Statement I: The main components are Ozone, Nitric oxide, Acrolein, Formaldehyde, and PAN (Peroxyacetyl nitrate). True.
• Statement II: Ozone, a major component of photochemical smog, attacks the double bonds in rubber, causing it to harden and crack (ozone cracking). True.
• Statement III: Since it contains high concentrations of oxidizing agents like Ozone and PAN, it is termed as Oxidizing Smog. (Classical smog is reducing). True.

Step 3: Conclusion:
All three statements are correct.