Question

Formation of photochemical smog involves the following reaction in which A, B, and C are respectively:
\(\text{NO}_2 \xrightarrow{h\nu} \text{A} + \text{B}\)
\(\text{B} + \text{O}_2 \rightarrow \text{C}\)
\(\text{A} + \text{C} \rightarrow \text{NO}_2 + \text{O}_2\)
Choose the correct answer from the options given below:

• A. NO, O, and O₃
• B. N₂O and NO
• C. N, O₂, and O₃
• D. O, NO, and NO₃

Answer 1

The Correct Option is A

Step 1: Breakdown of Reactions
Reaction (i): \(\text{NO}_2\) undergoes photodissociation under sunlight:
\[\text{NO}_2 \xrightarrow{h\nu} \text{NO (A)} + \text{O (B)}.\]
Reaction (ii): The oxygen radical (B) reacts with molecular oxygen to form ozone:
\[\text{O (B)} + \text{O}_2 \rightarrow \text{O}_3 (\text{C}).\]
Reaction (iii) \(\text{NO (A)}\) reacts with ozone to regenerate \(\text{NO}_2\) and molecular oxygen:
\[\text{NO (A)} + \text{O}_3 (\text{C}) \rightarrow \text{NO}_2 + \text{O}_2.\]
Step 2: Identify A, B, and C
From the reactions:
\(\text{A} = \text{NO}\) (Nitric oxide),
\(\text{B} = \text{O}\) (Oxygen radical),
\(\text{C} = \text{O}_3\) (Ozone).
Conclusion: The correct answer is (4) NO, O, and O\(_3\)