Environmental chemistry practice · Easy

Option B (Industrial wastes) is correct because industrial effluents often contain a wide variety of pollutants, including heavy metals and toxic chemicals, making them a significant source of water pollution.

Option A (Action of UV rays on oxygen) is correct because ozone in the upper atmosphere is formed when UV radiation from the sun splits oxygen molecules (O2) into individual oxygen atoms, which then combine with other O2 molecules to form ozone (O3).

Option B (Burning garbage) is correct because burning garbage often contains mercury-containing items, leading to mercury emissions.

Option B ($\mathrm{H}_2 \mathrm{SO}_4$) is correct because sulfuric acid is a major component of acid rain and reacts with the calcium carbonate in marble.

Option B (Kill germs) is correct because chlorine is added to water to disinfect it by killing bacteria and other microorganisms.

Option A ($5\mathrm{ }ppm$) is correct because a dissolved oxygen level of 5 ppm is generally considered necessary for a healthy aquatic ecosystem.

Option D is correct because green chemistry focuses on using non-toxic substances to create environmentally friendly products.

Option C (Industrial waste mercury into fishing water) is correct because Minamata disease is caused by mercury poisoning due to the consumption of fish contaminated with industrial mercury waste.

Correct Answer + Core Reason: Option C (Oxides of sulphur and nitrogen) is correct because smog is primarily caused by the presence of oxides of sulfur and nitrogen in the atmosphere.

Option B (Methyl isocyanate) is correct because methyl isocyanate (MIC) was the poisonous gas released during the Bhopal tragedy.

Option C is correct because catalytic converters reduce nitrogen oxides, a key component of photochemical smog.

Option A (Chlorofluorocarbon) is correct because Chlorofluorocarbons (CFCs) are the primary cause of ozone layer depletion.

Option C (AT and GC) is correct because adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C) in DNA.

Option B (oxidising smog) is correct because photochemical smog, which occurs in sunlight, is characterized by the presence of oxidizing agents like ozone and peroxyacetyl nitrate (PAN).

Option B (Anoxia) is correct because anoxia refers to the deficiency of oxygen reaching the tissues, which can occur at high altitudes due to lower atmospheric pressure and reduced oxygen availability.

Option B (Hydroelectric power) is correct because hydroelectric power generation does not directly release pollutants into the air, unlike industries and automobiles.

Option B (Paddy field) is correct because paddy fields are known to produce methane gas due to anaerobic decomposition of organic matter.

Option C (Both (1) and (2)) is correct because both Methyl chloroform and Carbon tetrachloride are known to contribute to the depletion of the ozone layer.

Option C ($5.5 - 7$) is correct because a fertile soil typically has a pH range of 5.5 to 7, which is slightly acidic to neutral, allowing for optimal nutrient availability for plants.

Option D (CO2) is correct because carbon dioxide is a major greenhouse gas that contributes significantly to the greenhouse effect.

Option C (Exosphere) is correct because the exosphere is the outermost layer of Earth's atmosphere, gradually merging with interplanetary space.

Option D (Forming stable compound with haemoglobin) is correct because carbon monoxide binds strongly to hemoglobin, preventing oxygen transport.

Option A (Stratosphere) is correct because the ozone layer, which absorbs harmful UV radiation, is located in the stratosphere.

Option A (Pathogens) is correct because pathogens, disease-causing microorganisms, pose the most immediate and serious threat to human health in water pollution.

Option A (Both S-I $\& S-II are correct) is correct because the receptor is the medium affected by pollutants, and the sink is the medium that reacts with pollutants.$

Option B (Nitrogen peroxide) is correct because Nitrogen dioxide (NO2), commonly referred to as nitrogen peroxide, is a primary pollutant.

Option D (All of the above) is correct because sulfur dioxide causes respiratory problems, reduces plant productivity through acid rain, and corrodes building materials.

Option B (Methane) is correct because methane is the most abundant hydrocarbon pollutant.