Question

Assertion :Photochemical smog is mainly composed of nitrogen oxides, volatile organic compounds, ozone and peroxyacyl nitrates. Reason: Photochemical smog develops in cold weather conditions by the interaction of secondary pollutants.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is C Assertion is correct but Reason is incorrect

Photochemical smog is a condition that develops when primary pollutants (such as oxides of nitrogen and volatile organic compounds) interact under the influence of sunlight to produce a mixture of secondary pollutants. Thus photochemical smog is mainly composed of oxides of nitrogen volatile organic compounds (primary pollutants), ozone and peroxyacyl nitrate, PAN (secondary pollutants), It was first reported over Los angels in 1940s. Photochemical smog is formed at high temperature over cities and towns due to still air, emission of nitrogen oxides and hydrocarbons from automobile exhausts and solar energy. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with carbohydrates to form aldehydes and ketones.
Reaction inside engine
$N_2+O_2⟶2NO$
Reaction in atmosphere
$2NO+O_2⟶{2NO}_2$
Photochemical reactions
${NO}_2⟶NO+\left[O\right]$
$O_2+\left[O\right]⟶O_3$
$NO+HC+O_2⟶{NO}_2+PAN$