Q.1 Which of the following is the primary cause of acid rain?
Carbon dioxide emissions
Sulfur dioxide and nitrogen oxides emissions
Methane emissions
Ozone depletion
Explanation - Acid rain is primarily caused by sulfur dioxide (SO2) and nitrogen oxides (NOx) which react with water to form sulfuric and nitric acids.
Correct answer is: Sulfur dioxide and nitrogen oxides emissions
Q.2 Which gas is mainly responsible for the greenhouse effect?
Oxygen
Nitrogen
Carbon dioxide
Hydrogen
Explanation - Carbon dioxide (CO2) traps heat in the atmosphere, contributing significantly to the greenhouse effect and global warming.
Correct answer is: Carbon dioxide
Q.3 The chemical formula of ozone is:
O2
O3
CO2
O4
Explanation - Ozone is a triatomic molecule with three oxygen atoms (O3). It absorbs harmful UV radiation in the stratosphere.
Correct answer is: O3
Q.4 Which of the following is a major pollutant in photochemical smog?
Sulfur dioxide
Nitrogen oxides
Chlorofluorocarbons
Ammonia
Explanation - Nitrogen oxides (NOx) react with volatile organic compounds (VOCs) in sunlight to form photochemical smog.
Correct answer is: Nitrogen oxides
Q.5 The process by which fertile land becomes desert due to deforestation or drought is called:
Eutrophication
Desertification
Deforestation
Salinization
Explanation - Desertification is the degradation of land in arid and semi-arid areas, often due to human activities or climatic variations.
Correct answer is: Desertification
Q.6 Which of the following is NOT a heavy metal pollutant?
Lead
Mercury
Cadmium
Sodium
Explanation - Sodium is not considered a heavy metal; heavy metals like lead, mercury, and cadmium are toxic even at low concentrations.
Correct answer is: Sodium
Q.7 The main source of groundwater contamination is:
Industrial effluents
Vehicle emissions
Deforestation
Ozone depletion
Explanation - Industrial effluents containing chemicals and heavy metals often seep into the ground, contaminating groundwater.
Correct answer is: Industrial effluents
Q.8 Which of the following contributes to eutrophication in water bodies?
Excess nitrogen and phosphorus
Excess oxygen
High acidity
Low salinity
Explanation - Eutrophication occurs due to nutrient enrichment, especially nitrogen and phosphorus, leading to excessive algae growth and oxygen depletion.
Correct answer is: Excess nitrogen and phosphorus
Q.9 Which pollutant is primarily responsible for the depletion of the ozone layer?
Carbon monoxide
CFCs (Chlorofluorocarbons)
Methane
Sulfur dioxide
Explanation - Chlorofluorocarbons (CFCs) release chlorine atoms in the stratosphere which catalytically destroy ozone molecules.
Correct answer is: CFCs (Chlorofluorocarbons)
Q.10 Biochemical Oxygen Demand (BOD) is a measure of:
Oxygen produced by plants
Oxygen consumed by microorganisms during decomposition
Total oxygen content in water
Oxygen released by animals
Explanation - BOD measures the amount of dissolved oxygen required by microorganisms to decompose organic matter in water, indicating water pollution levels.
Correct answer is: Oxygen consumed by microorganisms during decomposition
Q.11 The term 'smog' is a combination of:
Smoke and fog
Smoke and ozone
Sulfur and fog
Sulfur and oxygen
Explanation - The word 'smog' comes from combining 'smoke' and 'fog', describing a type of air pollution that reduces visibility.
Correct answer is: Smoke and fog
Q.12 Which of the following is a major source of indoor air pollution?
Cigarette smoke
Vehicle exhaust
Industrial emissions
Deforestation
Explanation - Cigarette smoke releases harmful chemicals indoors, making it a major contributor to indoor air pollution.
Correct answer is: Cigarette smoke
Q.13 Which method is commonly used for the removal of suspended solids from wastewater?
Sedimentation
Chlorination
Distillation
Electrolysis
Explanation - Sedimentation allows suspended particles to settle at the bottom due to gravity, removing solids from wastewater.
Correct answer is: Sedimentation
Q.14 Which chemical is commonly used to disinfect drinking water?
Sodium chloride
Chlorine
Sulfuric acid
Potassium permanganate
Explanation - Chlorine is widely used to kill bacteria and other pathogens in drinking water.
Correct answer is: Chlorine
Q.15 The 'London Smog' of 1952 was mainly caused by:
Vehicle emissions
Coal burning
Industrial gases
Volcanic eruption
Explanation - The London Smog was primarily due to the burning of large amounts of coal in homes and industries under stagnant weather conditions.
Correct answer is: Coal burning
Q.16 Which is the most abundant greenhouse gas in Earth's atmosphere?
Carbon dioxide
Methane
Water vapor
Nitrous oxide
Explanation - Water vapor is the most abundant greenhouse gas and contributes significantly to the natural greenhouse effect.
Correct answer is: Water vapor
Q.17 Heavy metals like mercury and cadmium can accumulate in living organisms, a process known as:
Biomagnification
Eutrophication
Photosynthesis
Volatilization
Explanation - Biomagnification is the increasing concentration of toxic substances like heavy metals as they move up the food chain.
Correct answer is: Biomagnification
Q.18 Which of the following is a secondary air pollutant?
Carbon monoxide
Sulfur dioxide
Ozone in the lower atmosphere
Methane
Explanation - Secondary pollutants are not emitted directly but form in the atmosphere through reactions of primary pollutants; ozone at ground level is a common secondary pollutant.
Correct answer is: Ozone in the lower atmosphere
Q.19 Which pollutant is mainly responsible for the blue haze observed in cities?
Ozone
Nitrogen dioxide
Particulate matter
Sulfur dioxide
Explanation - Fine particulate matter scatters light, causing the blue haze often observed in urban atmospheres.
Correct answer is: Particulate matter
Q.20 Which of the following is a major consequence of groundwater overexploitation?
Increase in aquifer levels
Land subsidence
Ozone layer depletion
Global warming
Explanation - Excessive withdrawal of groundwater causes land subsidence due to compaction of underground aquifers.
Correct answer is: Land subsidence
Q.21 Which of the following is used as a measure of air quality?
BOD
AQI (Air Quality Index)
pH
TDS
Explanation - AQI is an index for reporting daily air quality, indicating how polluted the air is and its health effects.
Correct answer is: AQI (Air Quality Index)
Q.22 Which gas released from landfills contributes significantly to the greenhouse effect?
Carbon dioxide
Methane
Oxygen
Nitrogen
Explanation - Methane (CH4) is released from anaerobic decomposition of organic matter in landfills and is a potent greenhouse gas.
Correct answer is: Methane
Q.23 Thermal pollution in water bodies is primarily caused by:
Organic waste discharge
Release of heated water from industries
Excessive fertilizers
Oil spills
Explanation - Industries discharge heated water into rivers or lakes, raising water temperature and affecting aquatic life, a phenomenon called thermal pollution.
Correct answer is: Release of heated water from industries
Q.24 Which of the following contributes to indoor radon pollution?
Decomposition of organic matter
Radioactive decay of uranium in soil
Cigarette smoke
Cooking with gas
Explanation - Radon is a radioactive gas produced by the decay of uranium in soil, which can accumulate indoors, posing health risks.
Correct answer is: Radioactive decay of uranium in soil
Q.25 Which of the following is an effect of ozone layer depletion?
Global warming
Increased UV radiation reaching Earth
Acid rain
Smog formation
Explanation - Ozone layer depletion allows more ultraviolet (UV) radiation to reach Earth's surface, leading to health and environmental issues.
Correct answer is: Increased UV radiation reaching Earth