NCERT Solutions For Class 11 Chemistry Chapter 14 Environmental Chemistry Multiple Choice Questions

NCERT Solutions For Class 11 Chemistry Chapter 14 Environmental Chemistry Multiple Choice Questions

Question 1. The ozone layer forms naturally by

1. The interaction of CFC with oxygen
2. The interaction of UV radiation with oxygen
3. The interaction of IR radiation with oxygen
4. The interaction of oxygen and water vapour

Answer: 2. The interaction of UV radiation with oxygen

The ozone layer forms naturally by the interaction of UV radiation with oxygen

Question 2. Among the following, the one which is not a “greenhouse gas” is

1. N₂O
2. CO
3. CH ₄
4. O

Answer: 4. O

O₂ is not a gas responsible for the rise in temperature of the earth. So, O₂ is not a ‘greenhouse gas.

Question 3. Metal ion responsible for the Minamata disease is

1. CO
2. Hg²⁺
3. Cu
4. Zn²⁺

Answer: 2. Hg²⁺

Hg²⁺ ion is responsible for the Minamata disease.

Question 4. What is DDT among the following

1. A fertilizer
2. Biodegradable pollutant
3. Non-biodegradable pollutant
4. Greenhouse gas

Answer: 3.  Non-biodegradable pollutant

DDT is a non-biodegradable pollutant

Question 5. The gas leaked from a storage tank of the Union Carbide plant in Bhopal gas tragedy was O₂

1. Phosgene
2. Methylisocyanate
3. Methylamine
4. Ammonia

Answer: 2. Methylisocyanate

Methylisocyanate gas was leaked from a storage tank of the Union Carbide plant in the Bhopal gas tragedy.

Question 6. The concentration of fluoride, lead, nitrate and iron in a water sample from an underground lake was found to be 1000 ppb, 40 ppb, 100 ppm and 0.2 ppm respectively. The water is unsuitable for drinking due to its high concentration.

1. Fluoride
2. Lead
3. Nitrate
4. Iron

Answer: 3. Nitrate

In the sample of water, the concentration of fluoride, lead and iron are in permissible limit but the concentration of nitrate ion is much higher than its permissible limit. Thus the water is not suitable for drinking.

Question 7. A water sample has ppm level concentration of the following anions, F^– = 10, SO₄^2-= 10, NO₃^– = 50. The anion/ anions that make/makes the water sample unsuitable for drinking is/are—

1. Only F^–
2. Only SO₄^2-
3. Only NO₃^–
4. Both SO₄^2- And NO₃^–

Answer: 1. Only F^–

In drinking water, if the concentration of SO₄^2- is more than 500 ppm, it shows a laxative effect and it is not suitable for drinking. If the concentration of SO₄^2-  is less than 500 ppm, it is consumable.

In drinking water, if the concentration of NO₃  ion is more than 50 ppm it causes methemoglobinemia disease. This is not suitable for drinking. If the concentration of F“ ion in drinking water is more than 1 ppm it damages teeth and bones. Thus it is not suitable for drinking.

Question 8. The recommended concentration of fluoride ion in drinking water is upto 1 ppm as fluoride ion is required to make teeth enamel harder

1. [3Ca₃(PO₄)₂ Ca(OH)₂]
2. [3Ca₃(PO₄)₂ .CaF₂]
3. [3{Ca(OH)₂} . CaF₂]
4. [3(CaF₂) . Ca(OH)₂]

Answer: 1. [3Ca₃(PO₄)₂ Ca(OH)₂]

Generally, tooth enamel is hydroxyapatite [3Ca₃(PO₄)₂ Ca(OH)₂].  Fluoride ion (F^–) reacts with hydroxyapatite to form a more rigid solid compound fluorapatite.

Question 9. Which one of the following statements is not true 

1. Oxides of sulphur, nitrogen and carbon are the most widespread air pollutants
2. PH of drinking water should be between 5.5-9.5
3. A concentration of DO below 6 ppm is good for the growth of fish
4. Clean water would have a BOD value of less than 5 ppm

Answer: 3.  A concentration of DO below 6 ppm is good for the growth of fish

Fish growth is facilitated if the DO value is less than 6 ppm. A decrease in the Do value means an increase in water pollution

Question 10. Which one of the following statements regarding photochemical smog is not correct

1. Photochemical smog is formed through a photochemical reaction involving solar energy
2. Photochemical smog does not irritate the eyes and throat
3. Carbon monoxide does not play any role in photochemical smog formation
4. Photochemical smog is an oxidising agent in character

Answer: 2. Photochemical smog does not irritate eyes and throat

Question 11. Which one of the following is not a common component of photochemical smog

1. Ozone
2. Acrolein
3. Peroxyacetyl nitrate
4. Chlorofluorocarbons

Answer: 4. Chlorofluorocarbons

Question 12. Which of the following is a sink for CO

1. Microorganisms present in the soil
2. Oceans
3. Plants
4. Haemoglobin

Answer: 1.  Microorganisms present in the soil

Question 13. Which oxide of nitrogen is not a common pollutant introduced into the atmosphere both due to natural and human activity

1. NO
2. N₂O₅
3. N₂O
4. NO₂

Answer: 2.  N₂O₅

Question 14. Living in the atmosphere of CO is dangerous because it

1. Combines with O₂ present inside to form CO₂
2. Reduces organic matter of tissues
3. Combines with haemoglobin and makes it incapable of absorbing oxygen
4. Dries up the blood

Answer: 3. Combines with haemoglobin and makes it incapable of absorbing oxygen

Question 15. Which of the following is not a greenhouse gas

1. Hydrogen
2. Carbon dioxide
3. Methane
4. Nitrous oxide or NO₂

Answer: 1.  Hydrogen

Carbon dioxide, methane, water vapour, nitrous oxide, CFCs and ozone are greenhouse gases.

Question 16. Which of the following has the highest concentration of PAN

1. Smoke
2. Ozone
3. Photochemical smog
4. Reducing smog

Answer: 3.  Photochemical smog

The main component of photochemical smog is peroxyacetyl nitrate, (PAN). The other components are ozone, nitric oxide, acrolein and formaldehyde.

Question 17. Which of the following is not a greenhouse gas?

1. Carbon dioxide
2. Water vapours
3. Methane
4. Oxygen

Answer: 4.  Oxygen

Carbon dioxide, water vapours and methane are greenhouse gases

Question 18. Which air pollutants do not evolve from motor vehicles

1. Formaldehyde
2. Carbon dioxide
3. Fly ash
4. Sulphur dioxide

Answer: 3. fly ash

Question 19. The top layer of the atmosphere is

1. Stratosphere
2. Troposphere
3. Exosphere
4. Ionosphere

Answer: 3. Exosphere

Question 20. Which of the following is not an air pollutant

1. NO
2. CO
3. O₃
4. C_xH_y

Answer: 2. CO

Question 21. Which of the following has the highest affinity towards haemoglobin 

1. CO
2. NO
3. O₂
4. CO₂

Answer: 1. CO

Question 22. Which gas is not present in the ozone layer

1. O₂
2. O₃
3. N₂
4. CO

Answer: 4. CO

Question 23. Fluoride pollution mainly affects

1. Teeth
2. Brain
3. Kidney
4. Heart

Answer: 1.  Teeth

Question 24. Which metal is mainly responsible for the decline of the Roman Empire

1. Copper
2. Lead
3. Arsenic
4. Zinc

Answer: 2.  Lead

Question 25. Which of the given pollutants does not affect the lungs

1. CO
2. SO₂
3. CO
4. NO

Answer: 3. CO

Question 26. Which of the following statements is not true

1. Ozone gas has no role in the greenhouse effect
2. Ozone gas oxidises sulphur dioxide of the atmosphere to sulphur trioxide
3. Gradual thinning of the ozone layer leads to the formation of an ozone hole
4. Oxygen molecule in the stratosphere forms ozone molecules in the presence of ultraviolet radiation

Answer: 1.  Ozone gas has no role in the greenhouse effect

Question 27. Although nitrogen and oxygen are the major constituents of air, they do not react with each other to produce oxides of nitrogen because

1. As the reaction is exothermic, a high temperature is required
2. A catalyst is required for the initiation of the reaction
3. Oxides of nitrogen are unstable
4. Nitrogen and oxygen do not take part in the reaction

Answer: 1. As the reaction is exothermic, a high temperature is required

Question 28. Which of the following is a secondary air pollutant

1. CO
2. CH
3. PAN
4. NO

Answer: 3. PAN

Question 29. Which of the given fuels used in motor vehicles is not environment friendly

1. Dye
2. Petrol
3. LPG
4. CNG

Answer: 4. LPG

Question 30. A major source of methane in India

1. Fruit garden
2. Sugarcane field
3. Paddy fields
4. Wheat fields

Answer: 3.  Paddy fields

Question 31. Cause of stenosis diseases

1. Fly ash
2. Cement particles
3. Cotton fibre
4. Lead particles

Answer: 3.  Cotton fibre

Question 32. The poisonous substance used in the paper is

1. Cadmium
2. Lead
3. Manganese
4. Mercury

Answer: 2.  Lead

Question 33. Which reaction is carried out in the catalytic converter of motor vehicles to eliminate NO_x from smoke

1. Oxidation
2. Reduction
3. Both oxidation-reduction
4. None

Answer: 2. Reduction

Question 34. Which of the following causes depletion in the ozone layer directly

1. SO₂
2. CFCs
3. H₂O
4. NO

Answer: 1. SO₂

Question 35. The incomplete combustion of gasoline produces

1. CO₂
2. CO
3. SO₂
4. NO₂

Answer: 2. CO

Question 36. Value of pH in drinking water—

1. Between 5.3 to 6.5
2. <5.5
3. Between 5.5 to 9.5
4. 9.5

Answer: 3. Between 5.5 to 9.5

Question 37. The radiation has a specific biological effect but is unable to cause Ionisation Is

1. UV-radiation
2. β -ray
3. X-ray
4. y-ray

Answer: 1.UV-radiatlon

Question 38. Which of the following compounds increases the BOD value of the water supply

1. CO₂
2. O
3. H₂O
4. CHOH

Answer: 4.  CHOH

Question 39. Which is most harmful for a human being

1. UV- A
2. UV – BOD
3. UV – CO₂
4. UV- DDT

Answer: 2. UV – BOD

Question 40. DDT and BHC are

1. Antibiotic
2. Chemical fertilizer
3. Non-biodegradable pollutant
4. Biodegradable compound

Answer: 3.  Non-biodegradable pollutant

Question 41. Which component of motor vehicle smoke causes nerve and mental diseases

1. Hg
2. SO₂
3. Pb
4. NO

Answer: 3. Pb

Question 42. Which mercury compound is the most toxic

1. CH₃Hg⁺
2. HgCl₂
3. Hg₂Cl₂
4. Hg metal

Answer: 1. CH₃Hg⁺

Question 43. Example of herbicide

1. DDT
2. Triazines
3. Methylmercury
4. PCBS

Answer: 2.  Triazines

Question 44. Nitrogen oxide is not a major air pollutant

1. NO₂
2. N₂O
3. NO
4. N₂O₅

Answer: 4. N₂O₅

Question 45. pH of natural rainwater

1. 6.5
2. 3.5
3. 4.6
4. 5.6

Answer: 4. 4.6

Question 46. Which water pollutant metal causes sterility disease

1. Cu
2. Hg
3. Cd
4. Mn

Answer: 4.  Mn

Question 47. The minimum permissible level of sound pollution is

1. 75 dB
2. 65 dB
3. 55 dB
4. 50 dB

Answer: 1. 75 dB

Question 48. In acid rain which of the following are present

1. H₂CO₃
2. HNO₃
3. CH₃COOH
4. H₂SO₄

Answer: 1, 2, and 4

Question 49. If fertilizer containing phosphate is dissolved in water

1. The amount of dissolved oxygen decreases
2. Calcium phosphate precipitates
3. Growth of fish increases
4. The growth of aquatic plants increases

Answer: 1 and 4

Question 50. Result of global warming

1. The temperature of the earth’s surface will increase
2. Glaciers of the Himalayan region will melt
3. Demand for biochemical oxygen will increase
4. Eutrophication

Answer: 1 and 2

Question 51. Which are responsible for photochemical smog

1. Oxides of nitrogen
2. Hydrocarbons
3. Carbon monoxide
4. Nobel gases

Answer: 1, 2, and 3

Question 52. Which gases absorb IR radiation

1. O₂
2. NO₂
3. CO
4. CFC

Answer: 3 and 4

Question 53.  Depletion in the ozone layer is caused by

1.  So₂
2. Halons
3. NO
4. C_xH_y

Answer: 2 and 3

Question 54. Which of the following states are responsible for environmental pollution

1. pH value in rainwater is 5.6
2. Eutrophication
3. The BOD value in the water sample is 15 ppm
4. The amount of CO₂ in the atmosphere is 0.03%

Answer: 2, and 3

Question 55. Which processes occur in the troposphere

1. Photosynthesis
2. Combustion
3. Greenhouse effect
4. Acid rain

Answer: 1, 2, 3 and 4

Question 56. Which statements are true

1. Mainly the effects of HNO₃ are more in acid rain
2. NO is more toxic than NO₂
3. Ozone gas is responsible for the greenhouse effect
4. IR radiation cannot pass through CO₂ gas but gets absorbed by it

Answer: 3 and 4

Question 57. Which radical causes depletion in the Ozone layer

1. CH₃
2. F
3. Cl
4. Br

Answer: 3 and 4

Question 58. Which greenhouse gases are produced in the agriculture field

1. CH₄
2. NH
3. Nobel
4. SO

Answer: 1 and 4

Question 59. Which are the following statements are incorrect

1. SO₂ does not affect the larynx
2. SO₂ is a more harmful pollutant than SO₃
3. In the case of living cells NO₂ is more toxic than NO
4. There is no role of NO_x in photochemical smog

Answer: 1, 2 and 4

Question 60. Diseases caused by the harmful effects of SO₂ 

1. Digestion problem
2. Breathing problem
3. Bronchitis
4. Asthma

Answer: 2, 3 and 4

Question 61. Which of the following processes are responsible for the formation of CO₂ in the atmosphere

1. Respiration
2. Combustion of fossil fuel
3. Decay of animals
4. Production of cement in factories

Answer: 2 and 4

Question 62. Which of the following react to produce PAN

1. NO
2. O₂
3. Hydrocarbon
4. CO

Answer: 1, 2 and 3

Question 63. Which constituents of phytochemicals responsible for eye irritation

1. Ozone
2. PAN
3. Hydrocarbon
4. O₂

Answer: 1 and 2

Question 64. The main constituents of London smog are

1. Oxides of sulphur
2. O₂
3. O₃
4. Oxides of nitrogen

Answer: 1 and 4

Question 65. Which of the following is responsible for the depletion of the ozone layer in the stratosphere

1. So
2. CFCl
3. CF
4. CF Br

Answer: 2 and 4

Question 66. Which of the following are primary pollutants

1. PAN
2. SO
3. NOz
4. Me₂Hg

Answer: 2 and 3

Question 67. Contribution of CO₂ and CH₄ in greenhouse effects

1. The contribution of CO₂ is 50%
2. The contribution of CH₄ is 16%
3. The contribution of CO₂ is 19%
4. The contribution of CH₄ is 19%

Answer: 1 and 4

Question 68. In which region there is a greater possibility of formation of photochemical smog

1. The region where a large number of automobiles are used
2. Region where sulphur-containing coal is used
3. Marshy land region
4. Orest region

Answer:  1. Region where a large number of automobiles are used

Question 69.  Acid rain is a dilute aqueous solution of which of the following pairs of acids

1. H₂SO₄ and HCl
2. H₂CO₃ and HCl
3. H₂SO₄ and HNO₃
4. H₂CO₃ and HCl

Answer: 3 . H₂SO₄ and HNO

Question 70. Which of the following metallic air pollutants is present in the gas emitted by motor vehicles

1. Iron
2. Lead
3. Copper
4. Mercury

Answer: 2.  Lead

Question 71.  Which of the following is not a Greenhouse gas

1. CFCs
2. Ammonia
3. Carbon dioxide
4. Methane

Answer: 2. Ammonia

Question 72. Which compound is responsible for hole formation in the stratosphere of the ozone layer

1. C₆F₆
2. C₆H₄Cl₂
3. CCl₂F₂
4. C₆H₆

Answer: 3. CCl₂F₂

Question 73. Which of the following gases emitted by motor vehicles is responsible for the formation of photochemical smog

1. SO₂
2. CO
3. NO
4. CO₂

Answer: 3. NO