JEE Main 12 Jan 2019 Morning Question 28
Question: The molecule that has minimum/no role in the formation of photochemical smog, is [JEE Main Online Paper Held On 12-Jan-2019 Morning]
Options:
A) $ CH _2=O $
B) $ N _2 $
C) $ O _3 $
D) ${NO}$
Show Answer
Answer:
Correct Answer: B
Solution:
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${N _2}$ molecule has minimum role in the formation of photochemical smog. While $ CH _2=O $ , $ O _3 $ 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; $ NO _2 $ (g) $\xrightarrow{h\nu} $ ${NO}$ (g) + ${O} (g)$
${O} (g)$ + $ O _2 $ (g) ⇌ $ O _3 $ (g)
${NO}$ (g) + $ O _3 $ (g) → ${NO _2}$ (g) + $ O _2 $ (g)$ O _3 $ (g) Reacts with unburnt hydrocarbons to produce chemicals such as formaldehyde, acrolein and PAN.3CH4 + 2O3 → 3CH2 = O + 3H2O + CH2 = CCH = O
