Which of the following are true about Polycyclic Aromatic Hydrocarbons (PAHs)?

A. They are potent carcinogenic air pollutants.
B. They are formed when minimum 10 (ten) benzene rings are fused together.
C. Formaldehyde is an example of PAH.
D. They are formed due to combustion of fossil fuels.

Choose the most appropriate answer from the options given below:

Correct option is D

Polycyclic Aromatic Hydrocarbons (PAHs) are a class of organic compounds composed of multiple fused aromatic (benzene) rings. They are well-known as potent carcinogenic air pollutants (A) and are primarily formed during the incomplete combustion of fossil fuels and other organic matter (D).

Statement B is incorrect because PAHs are generally formed by the fusion of 2 to 7 benzene rings, not a minimum of 10. Larger PAHs do exist but are rare and not typical of most environmental PAHs.

Statement C is incorrect because Formaldehyde is not a PAH; it is a simple aldehyde (CH₂O), unrelated chemically to the fused aromatic ring structure characteristic of PAHs.

Information Booster:

1. PAHs are generated by combustion processes including vehicle emissions, industrial activities, and burning of coal and wood.

2. They are lipophilic and can accumulate in the environment and human tissues.

3. Several PAHs are mutagenic and carcinogenic, leading to serious health concerns.

4. Common PAHs include naphthalene (2 rings), anthracene (3 rings), benzo[a]pyrene (5 rings).

5. PAHs can also form during grilling or smoking of food.

6. Their environmental persistence and toxicity make them important pollutants to monitor.

7. They contribute to air, water, and soil pollution globally.

Additional Information:

• (a) A: True; PAHs are carcinogenic air pollutants.

• (b) A and B Only: Incorrect due to wrong information in B.

• (c) B and C Only: Incorrect, both B and C are wrong.

• (d) A and D Only: Correct answer; both statements are true and accurate.