Question

Some reactions of $NO _2$ relevant to photochemical smog formation are 

Identify $A , B , X$ and $Y$

• A. $X =[ O ], Y = NO , A = O _2, B = O _3$
• B. $X = N _2 O , Y =[ O ], A = O _3, B = NO$
• C. $X =\frac{1}{2} O _2, Y = NO _2, A = O _3, B = O _2$
• D. $X = NO , Y =[ O ], A = O _2, B = N _2 O _3$

Answer 1

The Correct Option is A

To solve this question, we need to understand the role of various compounds in the formation of photochemical smog.

Step 1: Reaction Breakdown

The given image represents the decomposition of nitrogen dioxide (\(NO_2\)) under sunlight, a crucial step in the formation of photochemical smog. This can be broken down into the following reactions:

• Under the influence of sunlight, \(NO_2\) dissociates:
• \(NO_2 \xrightarrow{sunlight} NO + O\cdot\)

From the above, we can see that:

• X = [ O ]
• Y = NO

Step 2: Further Reactions

• The nascent oxygen \([ O ]\) reacts with oxygen \(O_2\) to form ozone \(O_3\):
• \(O_2 + [O] \rightarrow O_3\)

Thus:

• A = O_2
• B = O_3

Conclusion:

The correct option is:

\(X = [ O ]\), \(Y = NO\), \(A = O_2\), \(B = O_3\)

Explanation of Incorrect Options:

• Other options do not correctly represent the reactions involved in photochemical smog formation.

This reaction mechanism is a crucial part of understanding how pollutants like ozone are formed in the atmosphere, affecting air quality.