Question

Which of the following chemicals is not involved in photochemical smog formation?

• A. $SO _{2}$
• B. $O _{3}$
• C. $NO _{2}$
• D. $NO$

Answer 1

Answer: (A)

Photochemical smog, reffer to summer smog reaction of sunlight, nitrogen oxides and volatile organic compounds in atmosphere.

(i) $NO + O _{2} \longrightarrow NO _{2}$

(ii) $NO _{2}(g) \stackrel{h v}{\longrightarrow } NO (g)+[ O ]$

(iii) $[ O ]+ O _{2} \longrightarrow O _{3}$

(iv) $O _{3}+ NO \longrightarrow NO _{2}+ O _{2}$

$\underset{\text{Nitrogen oxides}}{{2NO_{2}}}+\underset{\text{Water}}{{H_2O}} \to \underset{\text{Nitrous acid}}{{HNO_{2}}}+\underset{\text{Nitric acid}}{{HNO_{3}}}$