Question

The molecule that has minimum/no role is the formation of photochemical smog, is
1. N₂
2. CH₂ = O
3. NO
4. O₃

Answer 1

Correct Answer - Option 1 : N₂

Concept:

N₂ molecule has minimum role in the formation of photochemical smog. While CH₂ = O, O₃ and NO has major role. When fossil fuels are burnt, a variety of pollutions are emiited.

Two of them are hydrocarbons (unburnt) and NO. When these pollutants build upon high levels, a chain reaction occurs from their interaction with sunlight. The reactions involved in the formation of photochemical smog are as follows;

\({\rm{N}}{{\rm{O}}_2}\left( {\rm{g}} \right)\mathop \to \limits^{{\rm{hv}}} {\rm{NO}}\left( {\rm{g}} \right) + {\rm{O}}\left( {\rm{g}} \right)\)

O (g) + O₂ (g) ⇌ O₃ (g)

NO (g) + O₃ (g) → NO₂ (g) + O₂ (g)

O₃ (g) Reacts with unburnt hydrocarbons to produce chemicals such as formaldehyde, acrolein and PAN.

3CH₄ + 2O₃ → 3CH₂ = O + 3H₂O + CH₂ = CCH = O