Question

Brown haze produced in photochemical smog is due to:

• A. $NO$
• B. $NO_{2}$
• C. $\text{CH}_{3}\text{-}\underset{\overset{\left||\right.}{\text{O}}}{\text{C}}\text{OO-NO}_{2}$
• D. $CH_{2}=CH-CH=O$

Answer 1

Answer: (B)

Photochemical smog is initiated by the photochemical dissociation of $NO_{2}$ and the resulting secondary reactions involving unsaturated hydrocarbons, other organic compounds and free radicals, leading to the formation of organic peroxides and ozone.

Hydrocarbons $+O_{3},O_{2},O,NO_{2},NO$ ; peroxides, peroxyacetyl nitrate, formaldehyde, ozone aldehyde, acrolein, etc. oxidised hydrocarbons and ozone in the presence of humidity cause photochemical smog, which dissipates at night.