Assertion (A): Photochemical smog is oxidising in nature. Reason (R): Photochemical smog contains and , which are formed during the sequence of reactions. (i) Both A and R are correct and R is the correct explanation of A. (ii) Both A and R are correct but R is not the correct explanation ofA. (iii) Both A and R are not correct. (iv) A is not correct but R is correct.

Question

Philoid · Accepted Answer

(i) Both A and R are correct and R is the correct explanation of A.

Explanation: Photochemical smog is one of the types of pollution which generally results from the reaction of atmospheric chemicals and sunlight. The primary Photochemical smog component is the ozone along with this it also contains , acrolein, PAN (Peroxy Acetyl Nitrate) and volatile organic compounds like formaldehyde.

The formation of photochemical smog involves multiple reversible oxidation/reductions steps of nitrogen oxides, methane and sulphur oxides.

Now, both nitrogen dioxide and ozone acts as oxidising agents and react with unburnt hydrocarbons and produce other components of photochemical smog – PAN, formaldehyde and acrolein.