The question asks why carbon monoxide (CO) is a toxic pollutant. This requires understanding the physiological effects of CO on the human body, specifically its interaction with the blood's oxygen transport system.
C) CO binds to haemoglobin with an affinity 200–300 times greater than oxygen, forming carboxyhaemoglobin (COHb), which prevents oxygen transport to body tissues, causing asphyxiation. This option accurately describes the primary mechanism by which carbon monoxide poisoning occurs.
The question asks to identify the correct characteristics of classical smog (London smog) in contrast to photochemical smog. We need to evaluate each option based on the known properties of classical smog.
A) Occurs in cool, humid climates; is REDUCING in nature; consists of smoke, fog and SO₂/H₂SO₄; occurs in early morning when temperature is low. This option accurately describes all the key characteristics of classical smog. It forms in cool, humid conditions, is reducing due to sulfur compounds, and is composed of smoke, fog, and sulfur oxides, often appearing in the early morning.
The question asks about the formation of photochemical smog. We need to identify the primary precursors and conditions required for its formation, as well as the key products.
A) Hydrocarbons and oxides of nitrogen (NOₓ) in the presence of sunlight — the free radical chain reactions produce ozone, PAN, formaldehyde and acrolein. This option accurately describes the precursors (hydrocarbons and NOₓ), the energy source (sunlight), the nature of the reactions (free radical chain reactions), and the major products (ozone, PAN, formaldehyde, acrolein) of photochemical smog formation.
The question asks to identify the major components of photochemical smog based on NCERT guidelines. Photochemical smog is a type of air pollution that forms when sunlight reacts with nitrogen oxides and at least one volatile organic compound (VOC) in the atmosphere. Understanding the chemical reactions involved helps in identifying its key constituents.
Option D correctly lists Ozone (\(\text{O}_3\)), nitric oxide (\(\text{NO}\)), acrolein (\(\text{CH}_2\)=\(\text{CH-CHO}\)), formaldehyde (\(\text{HCHO}\)) and peroxyacetyl nitrate (PAN). These are all either primary precursors (like \(\text{NO}\)) or major secondary products of photochemical smog formation. Ozone is a key component, formed from the reaction of \(\text{NO}_2\) in sunlight. Acrolein, formaldehyde, and PANs are formed from the oxidation of hydrocarbons in the presence of nitrogen oxides and sunlight.
The question asks about the specific harmful effects of Peroxyacetyl Nitrate (PAN) in photochemical smog. We need to identify the correct statement describing PAN's impact on human health and the environment.
B) PAN is a powerful EYE IRRITANT and lachrymatory agent; it also damages plants by disrupting photosynthesis (causes bronzing/silvering of leaves) and causes respiratory problems. This statement accurately describes the major harmful effects of PAN on human health and vegetation.
The question asks about the harmful effects of photochemical smog. We need to identify the option that accurately lists these effects, covering various aspects like human health, plant life, and material damage.
Correct Option: A) Causes serious health issues: eye irritation (ozone and PAN act as eye irritants); respiratory problems (bronchitis, emphysema); plant damage (premature ageing, reduced photosynthesis); damage to rubber, painted surfaces and metals through cracking