Q.1 Which gas is primarily responsible for the greenhouse effect?
Oxygen
Carbon dioxide
Nitrogen
Helium
Explanation - Carbon dioxide traps heat in the Earth's atmosphere, contributing significantly to the greenhouse effect.
Correct answer is: Carbon dioxide
Q.2 What is the main cause of acid rain?
CO2 and CH4
SO2 and NOx
O3 and N2
H2O and O2
Explanation - Sulfur dioxide and nitrogen oxides combine with water vapor to form sulfuric and nitric acid, leading to acid rain.
Correct answer is: SO2 and NOx
Q.3 Which of the following is a major pollutant in photochemical smog?
Methane
Ozone
Carbon monoxide
Ammonia
Explanation - Ground-level ozone is a harmful component of photochemical smog formed by sunlight-driven reactions of NOx and VOCs.
Correct answer is: Ozone
Q.4 Which international agreement focuses on reducing substances that deplete the ozone layer?
Kyoto Protocol
Montreal Protocol
Paris Agreement
Basel Convention
Explanation - The Montreal Protocol (1987) regulates the use of ozone-depleting substances such as CFCs.
Correct answer is: Montreal Protocol
Q.5 Which heavy metal causes Minamata disease?
Lead
Mercury
Cadmium
Chromium
Explanation - Minamata disease is caused by mercury poisoning due to industrial wastewater contamination in Minamata, Japan.
Correct answer is: Mercury
Q.6 Which pollutant is responsible for blue baby syndrome?
Lead
Nitrates
Mercury
Carbon monoxide
Explanation - High nitrate levels in drinking water reduce oxygen-carrying capacity of blood, causing methemoglobinemia or blue baby syndrome.
Correct answer is: Nitrates
Q.7 The ozone hole is mainly observed over which region?
Arctic
Antarctica
Tropics
Europe
Explanation - The ozone hole forms over Antarctica due to the presence of polar stratospheric clouds and CFCs.
Correct answer is: Antarctica
Q.8 Which gas is called laughing gas and contributes to global warming?
Carbon monoxide
Nitrous oxide
Methane
Sulfur dioxide
Explanation - Nitrous oxide (N2O) is a greenhouse gas and also known as laughing gas in medical use.
Correct answer is: Nitrous oxide
Q.9 Which of the following is NOT a greenhouse gas?
Methane
Oxygen
Carbon dioxide
Nitrous oxide
Explanation - Oxygen is not a greenhouse gas because it does not absorb infrared radiation.
Correct answer is: Oxygen
Q.10 Eutrophication in water bodies is caused by excess of:
Oxygen
Nutrients like nitrates and phosphates
Carbon dioxide
Sulfur dioxide
Explanation - Excess nutrients cause algal blooms, depleting oxygen and leading to eutrophication.
Correct answer is: Nutrients like nitrates and phosphates
Q.11 Which of the following is considered a primary pollutant?
Ozone
Smog
Carbon monoxide
Peroxyacetyl nitrate
Explanation - Primary pollutants are directly emitted from sources; carbon monoxide is one of them.
Correct answer is: Carbon monoxide
Q.12 Which compound is responsible for ozone depletion?
Carbon monoxide
CFCs
Nitrogen gas
Ammonia
Explanation - Chlorofluorocarbons release chlorine atoms in the stratosphere, destroying ozone molecules.
Correct answer is: CFCs
Q.13 What does BOD stand for in environmental chemistry?
Biological Oxygen Demand
Basic Oxide Density
Biochemical Ozone Depletion
Bonding Oxygen Data
Explanation - BOD indicates the amount of oxygen required by microorganisms to decompose organic matter in water.
Correct answer is: Biological Oxygen Demand
Q.14 Which pollutant causes thinning of shells in birds?
DDT
CO2
Mercury
Ozone
Explanation - The pesticide DDT causes calcium metabolism disruption in birds, thinning eggshells.
Correct answer is: DDT
Q.15 Which gas is responsible for the characteristic smell of rotten eggs?
Methane
Hydrogen sulfide
Ammonia
Ozone
Explanation - Hydrogen sulfide (H2S) has a foul smell resembling rotten eggs.
Correct answer is: Hydrogen sulfide
Q.16 What type of smog is common in cities with high sunlight and traffic emissions?
London smog
Photochemical smog
Sulfur smog
Industrial smog
Explanation - Photochemical smog forms in presence of sunlight from NOx and VOCs in cities.
Correct answer is: Photochemical smog
Q.17 Which form of water pollution is measured by COD?
Chemical Oxygen Demand
Carbonate Oxide Deposition
Carbon Oxygen Density
Chlorine Oxide Demand
Explanation - COD measures the amount of oxygen needed to chemically oxidize pollutants in water.
Correct answer is: Chemical Oxygen Demand
Q.18 Which type of radiation is blocked by the ozone layer?
Infrared
Visible
Ultraviolet
Microwave
Explanation - Ozone absorbs harmful ultraviolet radiation from the sun, protecting living organisms.
Correct answer is: Ultraviolet
Q.19 The pH of acid rain is typically:
7
Less than 5.6
Between 6 and 7
Greater than 7
Explanation - Acid rain has a pH less than 5.6 due to dissolved sulfuric and nitric acids.
Correct answer is: Less than 5.6
Q.20 Which gas is produced during incomplete combustion of fossil fuels?
CO2
CO
NO2
SO2
Explanation - Carbon monoxide is produced during incomplete combustion and is a poisonous gas.
Correct answer is: CO
Q.21 Which heavy metal causes Itai-Itai disease?
Lead
Cadmium
Mercury
Chromium
Explanation - Itai-Itai disease in Japan was caused by cadmium poisoning from contaminated rice and water.
Correct answer is: Cadmium
Q.22 Which of the following is a biodegradable pollutant?
DDT
Plastic
Sewage
Mercury
Explanation - Sewage is biodegradable as it can be broken down by microorganisms.
Correct answer is: Sewage
Q.23 PAN (Peroxyacetyl Nitrate) is a component of:
Industrial smog
Photochemical smog
London smog
Natural air
Explanation - PAN is a toxic oxidant formed in photochemical smog by reaction of VOCs and NOx in sunlight.
Correct answer is: Photochemical smog
Q.24 Which of the following gases has the highest global warming potential (GWP)?
Carbon dioxide
Methane
CFCs
Nitrous oxide
Explanation - CFCs have very high GWP, thousands of times more than CO2.
Correct answer is: CFCs
Q.25 Which type of pollution is caused by excessive use of detergents in water?
Thermal pollution
Eutrophication
Air pollution
Soil pollution
Explanation - Detergents add phosphates to water, leading to eutrophication.
Correct answer is: Eutrophication