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Environmental Chemistry is the study of the relative chemical and biochemical reactions happening in our environmental factors. It manages the chemical species present in the environment, its origin, fate, transport, reactions, impacts, and what human exercises mean for the environment. Study of the chemical constituent of water, soil, and air is required, so environmental chemistry depends on different branches like insightful, soil, air, climatic, organic chemistry.

Check the given Chemistry MCQ Questions for class 11 Environmental Chemistry with Answers. Solve MCQ Questions for Class 11 Chemistry with answers as you will think about all of the concepts.

Practice MCQ Questions for class 11

1. The agricultural field that produces maximum methane gas into atmosphere is

(a) Wheat field
(b) Paddy field
(c) Cotton field
(d) Groundnut field

2. Fluorosis, the bone disease, is caused by the presence of

(a) Pesticides in water
(b) Fluorides in water
(c) Carbon monoxide in air
(d) Sulphur dioxide in air

3. The most harmful air pollutant produced by automobiles is

(a) HNO₃
(b) NO
(c) SO₂
(d) CO

4. Which of the following is responsible for depletion of ozone layer in the upper strata of the atmosphere?

(a) Polyhalogens
(b) Ferrocene
(c) Fullerencs
(d) Freons

5. Which of the following acts as a sink for CO?

(a) Plants
(b) Haemoglobin
(c) Microorganisms present in the soil
(d) Oceans

6. Domestic waste mostly constitutes

(a) Non-biodegradable pollution
(b) Biodegradable pollution
(c) Effluents
(d) Air pollution

7. Which is most harmful for life on globe?

(a) Deforestation
(b) Soil Erosion
(c) Increasing Desert
(d) Nuclear Fallout

8. A disease caused by eating fish contaminated by industrial waste, containing mercury compounds, is called as

(a) Minamata disease
(b) Brights disease
(c) Hashimotos disease
(d) Osteosclerosis

9. Green chemistry means such reasons which

(a) produce colour during reactions
(b) reduce the use and production of hazardous chemicals
(c) are related to the depletion of ozone layer
(d) study the reactions in plants

10. Which is the greatest air pollutant these days

(a) Factories
(b) Motor vehicles
(c) Domestic appliances
(d) animals

11. Which oxide of nitrogen is not a common pollutant introduced into the atmosphere both due to natural and human activity?

(a) N₂O₅
(b) NO₂
(c) N₂O
(d) NO

12. Among the following, the one that is not a green house gas is:

(a) sulphur dioxide
(b) nitrous oxide
(c) methane
(d) ozone

13. Which of the following practices will not come under green chemistry?

(a) If possible, making use of soap made of vegetable oils instead of using synthetic detergents.
(b) Using H₂O₂ for bleaching purpose instead of using chlorine based bleaching agents.
(c) Using bicycle for travelling small distances instead of using petrol/diesel based vehicles.
(d) Using plastic cans for neatly storing substances

14. The living organisms on or around the earth constitute

(a) Biome
(b) Biosphere
(c) Community
(d) Biocoenosis

15. Which country has the greatest contribution for the hole formation in ozone layer?

(a) Russia
(b) Japan
(c) USA
(d) Germany

16. The major source of BOD in the river Ganga is

(a) Leaf litter
(b) Fishes
(c) Human waste
(d) Aquatic plants

17. The substance having the largest concentration in acid rain?

(a) H₂CO₃
(b) HNO₃
(c) HCl
(d) H₂SO₄

18. Photochemical smog occurs in warm, dry and sunny climate. One of the following is not amongst the components of photochemical smog, identify it.

(a) NO₂
(b) O₃
(c) SO₂
(d) Unsaturated hydrocarbon

19. The type of pollution caused by spraying of DDT

(a) Air and soil
(b) Air and water
(c) Air
(d) Air, water and soil

20. The pollutants which come directly in the air from sources are called primary pollutants. Primary pollutants are sometimes converted into secondary pollutants. Which of the following belongs to secondary air pollutants?

(a) CO
(b) Hydrocarbon
(c) Peroxyacetyl nitrate
(d) NO

21. The gaseous envelope around the earth is known as atmosphere. The lowest layer of this is extended upto 10 km from sea level, this layer is ................

(a) Stratosphere
(b) Troposphere
(c) Mesosphere
(d) Hydrosphere

22. Biochemical Oxygen Demand, (BOd) is a measure of organic material present in water. BOD value less than 5 ppm indicates a water sample to be __________.

(a) rich in dissolved oxygen
(b) poor in dissolved oxygen
(c) highly polluted
(d) not suitable for aquatic life

23. Sewage containing organic waste should not be disposed in water bodies because it causes major water pollution. Fishes in such a polluted water die because of

(a) Large number of mosquitoes
(b) Increase in the amount of dissolved oxygen
(c) Decrease in the amount of dissolved oxygen in water
(d) Clogging of gills by mud

24. Which is not a renewable source

(a) sunlight
(b) Coal
(c) Water
(d) wind energy

25. When biosphere turns into human-dominated environment it is called

(a) Noosphere
(b) Troposphe
(c) Mesosphere
(d) Man sphere

Answer:

1. Answer : (b) Paddy field

Explanation: Rice crops are grown on paddy fields. Hence, the agricultural field that produces the maximum methane gas into the atmosphere is paddy field. 

2. Answer : (b) Fluorides in water

Explanation: Skeletal fluorosis is a bone disease caused by excessive accumulation of fluoride in the bones. In advanced cases, skeletal fluorosis causes painful damage to bones and joints.

3. Answer : (d) CO

Explanation: CO is odorless, colorless, and poisonous gas is formed by the combustion of fossil fuels such as gasoline and is emitted primarily from cars and trucks.

4. Answer : (d) Freons

Explanation: Freons or chlorofluoro carbons (CFC) are responsible for depletion of ozone layer in the upper strata of the atmosphere.They are used as propellants, aerosol spray caps, refrigerants, fire fighting reagents etc.

5. Answer : (c) Microorganisms present in the soil

Explanation: CO is converted into CO₂ by micro- organism present in soil.

6. Answer : (b) Biodegradable pollution

Explanation: Domestic waste mostly constitutes biodegradable pollution.

7. Answer : (d) Nuclear Fallout

Explanation: Nuclear fallout, or simply fallout, is the residual radioactive material propelled into the upper atmosphere following a nuclear blast or a nuclear reaction conducted in an unshielded facility.

8. Answer : (a) Minamata disease

Explanation: Mercury is changed to water soluble dimethyl mercury which undergoes biomagnification. Eating poisoned animals causes deformity known as Minamata disease (first reported in 1952 due to eating of fish captured from Hg-contaminated Minimata Bay of Japan) which is characterised by diarrhoea, hemolysis, impairment of various senses, numbness of lips, tounge, limbs, deafness, blurring of vision, mental dearrangement, meningitis and death.

9. Answer : (b) reduce the use and production of hazardous chemicals

Explanation: Green chemistry means such reactions which reduce the use and production of hazardous chemicals. Green chemistry is the use of chemistry for pollution prevention by an environmentally conscious design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances.

10. Answer : (b) Motor vehicles

Explanation: Motor vehicles are the greatest air pollutants these days as day by day with increase in population, the number of motor vehicles also increased and motor vehicles causes high emission of CO₂ ​gas, thereby causing pollution.

11. Answer : (a) N₂O₅

Explanation: Dinitrogen pentoxide is an unstable and dangerous oxidiser, which contains only nitrogen and oxygen. It is formed when oxygen and nitrogen react. In the atmosphere it attracts NOX gases that cause depletion of the ozone layer.

12. Answer : (a) sulphur dioxide

Explanation: The primary greenhouse gases present around us are carbon dioxide, methane, nitrous oxide, ozone and water vapours etc. Thus, the gas which is not green house gas from the options given to us is Sulphur dioxide.

13. Answer : (d) Using plastic cans for neatly storing substances

Explanation: Plastics are non-biodegradable, hence are not environmental friendly.

14. Answer : (b) Biosphere

Explanation: The biosphere is the region of the earth that encompasses all living organisms: plants, animals and bacteria.

15. Answer : (c) USA

Explanation: Depletion in the concentration of ozone over a restricted area as spring time decline over Antartica is called ozone hole. Depletion of ozone is due to action of sunlight over pollutants which release chemicals (e.g., chlorine) that destroy ozone. Major contributor of these gases is USA.

16. Answer : (c) Human waste

Explanation: The Ganges river basin is one of the most fertile and densely populated regions in the world that covers an area of 1,80,000 km². The river flows through 29 cities with population over 100,000; 23 cities with population between 50,000 and 100,000, and about 48 towns. A large proportion of the waste in the Ganges is from this population through domestic usage like bathing, laundry and public defecation. An analysis of the Ganges water in 2006 showed significant associations between waterborne or enteric disease due to the use of the river for bathing, laundry, washing, eating, cleaning utensils, and brushing teeth.

17. Answer : (d) H₂SO₄

Explanation: Sulphuric acid(H2SO4) is present in a larger concentration in acid rain. Acid rain is formed due to the presence of oxides of sulphur and nitrogen in the atmosphere.

18. Answer : (c) SO₂

Explanation: The smog which is formed in presence of sunlight is called photochemical smog. This occurs in the months of summer when NO₂ and hydrocarbons are present in large amounts in atmosphere.SO₂ is not responsible for photochemical smog because concentration of O₃. PAN, aldehyde and ketones builds up in the atmosphere.

19. Answer : (d) Air, water and soil

Explanation: Spraying of DDT chemicals leads to the pollution of the air, soil and water.  DDT and other agrochemicals are release greenhouse gasses to the environment which causes ozone depletion.

20. Answer : (c) Peroxyacetyl nitrate

Explanation: Peroxyacetyl nitrate (PAN), formed from the primary pollutants NO₂, O₃ and hydrocarbons, is the secondary pollutant.

21. Answer : (b) Troposphere

Explanation: Troposphere is the lowest region and extends upto 10 km from the sea level. This layer envelops 80% of the total mass of the air and  spreads widely. 

22. Answer : (a) rich in dissolved oxygen

Explanation: Clean water has BOD which is less than 5 ppm. If it is equal to or more than 12 ppm, then the water is considered as polluted. So this indicates water be rich in dissolved oxygen, that helps the microorganisms to oxidize inorganic and organic materials.

23. Answer : (c) Decrease in the amount of dissolved oxygen in water

Explanation: Low dissolved oxygen(DO) is usually the major contributor to fish kills, make some fish species more vulnerable to environmental stress.Fishkill can occur with rapid fluctuations in temperature or sustained high can lead decreased dissolved oxygen(DO) in a body of water.

24. Answer : (b) Coal

Explanation: Coal is classified as a nonrenewable energy source because it takes millions of years to form. Coal contains the energy stored by plants that lived hundreds of millions of years ago in swampy forests.

25. Answer : (a) Noosphere

Explanation: When biosphere turns into human dominated environment it is called noosphere. The noosphere is the sphere of human thought. The noosphere emerges through and is constituted by the interaction of human minds. The noosphere has grown in step with the organization of the human mass in relation to itself as it populates the Earth.As mankind organizes itself in more complex social networks, the higher the noosphere will grow in awareness.

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