18

Q1. DDT is now banned in countries such as India.

• 1) True
• 2) False

Solution

DDT is now banned in countries such as USA but not in India.

Q2. Algae are photosynthetic and hence add a large amount of oxygen to the water.

• 1) False
• 2) True

Solution

Algae compete with aquatic organisms for oxygen and deplete the oxygen levels in water bodies.

Q3. Industrialisation and rising population are the contributors for global warming.

• 1) True
• 2) False

Solution

True

Q4. How does the Indian legal system protect the Taj Mahal from pollution?

Solution

The Supreme Court of India has ordered industries in and around the Taj Mahal to switch to LPG and CNG. It has also ordered vehicles to switch to unleaded petrol in the Taj zone to reduce pollution in the area and to protect the monument.

Q5. During the last three decades, the temperature of the Earth’s atmosphere has increased by 5°C.

• 1) False
• 2) True

Solution

During the last three decades, the temperature of the Earth’s atmosphere has increased by 0.5°C.

Q6. Which of the following is an indicator of pollution of water bodies?

• 1) Level of oxygen
• 2) Presence of algae
• 3) Presence of decomposers
• 4) Bacteria present in the faeces of mammals living in water

Solution

Bacteria present in the faeces of mammals in water are an indicator of the pollution or quality of water.

Q7. The Ganga Action Plan was initiated in

• 1) 1990
• 2) 1985
• 3) 1980
• 4) 1995

Solution

The Ganga Action Plan was initiated in 1985. It aimed to reduce the pollution levels of the river.

Q8. Expand DDT.

Solution

DDT - Dichlorodiphenyltrichloroethane

Q9. Algae are photosynthetic and hence add a large amount of oxygen to the water.

• 1) False
• 2) True

Solution

Algae compete with aquatic organisms for oxygen and deplete the oxygen levels in water bodies.

Q10. Fertilisers contaminate only lakes and rivers and do not affect oceans.

• 1) True
• 2) False

Solution

Fertilisers washed into the rivers and lakes ultimately find their way to the seas and oceans polluting them as well.

Q11. Eutrophication is the process of killing algae in water by using chemicals.

• 1) False
• 2) True

Solution

Excessive growth of algae in water bodies is called eutrophication.

Q12. Complete burning of fossil fuels is the major source of CO_2­ in the atmosphere.

• 1) True
• 2) False

Solution

Incomplete burning of fossil fuels is responsible for release of CO.

Q13. Porcelain filters are used to remove viruses from water.

• 1) False
• 2) True

Solution

Porcelain filters cannot remove viruses from water.

Q14. What are the major sources of the following pollutants: 1. Particulate matter 2. Chlorofluorocarbons

Solution

1. Particulate matter- Volcanic eruptions, dust storms, burning of fossil fuels are the natural sources of these pollutants. 2. Chlorofluorocarbons- Coolants in refrigerators and air conditioners and propellants in aerosol apray cans, plastic foams are common sources of these CFCs.

Q15. Which fuel reduces air pollution?

• 1) Both CNG and LPG
• 2) CNG
• 3) LPG
• 4) Petrol

Solution

Use of CNG and LPG is encouraged as they are eco-friendly and do not cause as much pollution as conventional fuels.

Q16. The rise in the sea level is a cause of water pollution.

• 1) True
• 2) False

Solution

The rise in the sea level is a cause of global warming.

Q17. Fertiliser waste dumped into rivers is a cause for algal blooms.

• 1) False
• 2) True

Solution

True

Q18. Mining activities release particulate pollutants in the air.

• 1) True
• 2) False

Solution

True

Q19. List a few disease-causing microorganisms which can be found in sewage water.

Solution

Sewage carries the microorganisms for certain water-borne diseases such as cholera, dysentery, jaundice, typhoid and diarrhoea.

Q20. Fertilisers promote the growth of algae in water.

• 1) False
• 2) True

Solution

True

Q21. Global warming is the indirect cause for extinction of the polar bear.

• 1) False
• 2) True

Solution

True

Q22. How does a UV filter help purify water?

Solution

A UV (ultraviolet) filter makes use of ultraviolet light to kill microorganisms, thus making the water fit for consumption.

Q23. Which of the following element is mostly released from agricultural fields into the water bodies?

• 1) Nitrogen
• 2) Nickel
• 3) Mercury
• 4) Calcium

Solution

Nitrogen forms an important and major component of fertilisers used in agricultural fields and is the major water pollutant released from agricultural fields.

Q24. When the algae in a polluted river die, the population of which of the following organisms increases?

• 1) Bacteria
• 2) Fish
• 3) Plankton
• 4) Frogs

Solution

When algae growing abundantly in a polluted river die, the population of decomposing bacteria increases as it feeds on dead algae.

Q25. (i)What is trapping of radiation of sun by the atmosphere of the earth called? Explain the process. (ii)Name any two gases responsible for above phenomenon.

Solution

(i) Green house effect the sun sends its rays to the earth. Some of these rays are absorbed by the earth atmosphere and some radiations are reflected back. Thus, cover of green house gases does not allow the heat rays to leave earth's atmosphere completely. This effect keeps earth's atmosphere warm. (ii) CO₂, Methane(CH₄)

Q26. The range of pH for acidic rain is

• 1) 7
• 2) Below 7
• 3) 14
• 4) Above 7

Solution

A liquid with pH values less than 7 is acidic.

Q27. What are the acids responsible for the formation of acid rain?

• 1) Sulphuric acid and carbonic acid
• 2) Carbonic acid and acetic acid
• 3) Sulphuric acid and hydrofluoric acid
• 4) Carbonic acid only

Solution

The sulphuric and carbonic acids formed in the atmosphere fall to the ground mixed with rain, snow, fog, or hail called as acid rain.

Q28. Industrialisation and rising population are the contributors for global warming.

• 1) False
• 2) True

Solution

True

Q29. Acid rain is a cause of water pollution.

• 1) False
• 2) True

Solution

Acid rain is a cause of air pollution.

Q30. Global warming is the indirect cause for extinction of the polar bear.

• 1) True
• 2) False

Solution

True

Q31. Which of the following regions does not lie along River Ganga?

• 1) Kanpur
• 2) Varanasi
• 3) Patna
• 4) Kochi

Solution

Kochi lies in the southern part of India; it does not lie along the path of River Ganga.

Q32. Acid rain decreases the acidity of water bodies.

• 1) False
• 2) True

Solution

Acid rain increases the acidity of water bodies.

Q33. Give an example of an international agreement among different countries to reduce the emissions of greenhouse gases.

Solution

The Kyoto Protocol is an agreement which has been signed by various countries to reduce the emissions of greenhouse gases.

Q34. Which of the following is a less polluting form of petrol?

• 1) Leaded petrol
• 2) Sulphite petrol
• 3) Unleaded petrol
• 4) Diesel

Solution

As compared to leaded petrol, unleaded petrol is less polluting.

Q35. Acid rains are good for areas where the soil is excessively alkaline in nature.

• 1) True
• 2) False

Solution

Acid rain pollutes the soil and hence is not beneficial.

Q36. How does domestic wet waste contribute to air pollution?

Solution

Domestic wet waste is subject to decomposition and thus releases foul odour and CO₂ into the atmosphere, polluting the air.

Q37. Corrosion of marble due to acid rain is known as

• 1) Marble cancer
• 2) Lime cancer
• 3) Acid cancer
• 4) Calcium rust

Solution

The marble cancer refers to the corrosion of building and statues made up of marbles by the action of sulphuric acid and nitric acid.

Q38. Mopping the floor instead of washing is a good way of saving water.

• 1) True
• 2) False

Solution

True

Q39. Sulphur dioxide and nitrogen dioxide rise high and combine with the ozone depleting it.

• 1) False
• 2) True

Solution

Sulphur dioxide and nitrogen dioxide are responsible for acid rains and not ozone depletion.

Q40. A dripping tap can cause a loss of up to 72 litres of water per day. 

• 1) False
• 2) True

Solution

True

Q41. CO₂ combines with haemoglobin in the blood and forms carboxyhaemoglobin.

• 1) True
• 2) False

Solution

CO combines with haemoglobin in the blood and forms carboxyhaemoglobin.

Q42. Dysentery is a waterborne disease.

• 1) False
• 2) True

Solution

True

Q43. CO₂ helps in the retention of heat.

• 1) False
• 2) True

Solution

True

Q44. Industries which contribute towards the formation of acid rain are

• 1) All of these
• 2) Rubber processing industries
• 3) Chemical plants
• 4) Automobile industries

Solution

Industries such as rubber processing, oil refineries, chemical plants and automobile industry are responsible for the release of sulphur dioxide and nitrogen dioxide which cause acid rain.

Q45. Porcelain filters are used to remove viruses from water.

• 1) False
• 2) True

Solution

Porcelain filters cannot remove viruses from water.

Q46. In a food chain from zooplankton to man via various fish sizes, the largest amount of a chemical accumulated through biomagnification will be in only the small fish immediately after zooplankton.

• 1) True
• 2) False

Solution

In a food chain from zooplankton to man via various fish sizes, the largest amount of a chemical accumulated through biomagnification will be in man.

Q47. What is eutrophication?

Solution

Eutrophication may be defined as the process of increase in the nutrient content of the aquatic ecosystem followed by the excessive growth of algae and weeds on the water surface.

Q48. Fertilisers promote the growth of algae in water.

• 1) False
• 2) True

Solution

True

Q49. Potassium permanganate can be used as a disinfectant to purify water.

• 1) True
• 2) False

Solution

True

Q50. Yellowing of marble of the Taj Mahal is caused by

• 1) Soot
• 2) Iron
• 3) Smog
• 4) Rain

Solution

Yellowing of marble is caused by soot particles emitted by the Mathura oil refineries.

Q51. Which is the major source of carbon monoxide in the air in urban areas?

Solution

Automobiles in urban areas are the major sources of carbon monoxide in the air.

Q52. List four sources of sulphur dioxide in the air.

Solution

Burning of coal Metal smelting Paper production Industrial processes Thermal power plants (Any Four)

Q53. Acid rains are good for areas where the soil is excessively alkaline in nature.

• 1) False
• 2) True

Solution

Acid rain pollutes the soil and hence is not beneficial.

Q54. Fertilisers contaminate only lakes and rivers and do not affect oceans.

• 1) False
• 2) True

Solution

Fertilisers washed into the rivers and lakes ultimately find their way to the seas and oceans polluting them as well.

Q55. In a food chain from zooplankton to man via various fish sizes, the largest amount of a chemical accumulated through biomagnification will be in only the small fish immediately after zooplankton. 

• 1) True
• 2) False

Solution

In a food chain from zooplankton to man via various fish sizes, the largest amount of a chemical accumulated through biomagnification will be in man.

Q56. How do oil spills affect birds?

Solution

In oceanic regions, certain birds feed on fish which swim near the surface. To catch the fish, these birds dive into the water. When the birds dive in water which has oil spilled on its surface, the oil sticks to the feathers and makes the birds heavy and incapable of taking flight.

Q57. List some pollutants released in the air by industries.

Solution

Industries and factories release sulphur dioxide, carbon dioxide, particulate matter and dust into the air.

Q58. Acid rain decreases the acidity of water bodies.

• 1) False
• 2) True

Solution

Acid rain increases the acidity of water bodies.

Q59. Coal gas, coke, and coal are

• 1) Fossil fuels
• 2) Responsible for biogas formation
• 3) Responsible for ozone depletion
• 4) Causes of deforestation

Solution

Coal gas, coke, and coal are fossil fuels that burn to release CO₂ which causes global warming.

Q60. The rise in the sea level is a cause of water pollution.

• 1) True
• 2) False

Solution

The rise in the sea level is a cause of global warming.

Q61. Mopping the floor instead of washing is a good way of saving water.

• 1) False
• 2) True

Solution

True

Q62. Explain the effects of acid rain on: 1. Aquatic life 2. Statues and bridges

Solution

1. Acid rain disrupts the reproductive cycle of aquatic species. It also leaches aluminum from the soil into the water, clogging the fish's gills and altering their blood chemistry. As a lake becomes acidified, one species after another disappears. 2. Acids present in the acid rain corrodes metals resulting in weakening of the bridges. Acid rain dissolves marble and stone and hence damages the statues.

Q63. The Ganga Action Plan was launched in 1896.

• 1) False
• 2) True

Solution

The Ganga Action Plan was launched in 1986.

Q64. CO₂ combines with haemoglobin in the blood and forms carboxyhaemoglobin.

• 1) False
• 2) True

Solution

CO combines with haemoglobin in the blood and forms carboxyhaemoglobin.

Q65. Burning of garbage increases the levels of CO₂ in the atmosphere.

• 1) False
• 2) True

Solution

True

Q66. DDT is now banned in countries such as India.

• 1) False
• 2) True

Solution

DDT is now banned in countries such as USA but not in India.

Q67. What is marble cancer?

Solution

The corrosion of the marble of monuments due to acids present in acid rain is called marble cancer.

Q68. Eutrophication is the process of killing algae in water by using chemicals.

• 1) False
• 2) True

Solution

Excessive growth of algae in water bodies is called eutrophication.

Q69. Emission of radioactive elements does not affect the air.

• 1) False
• 2) True

Solution

Emissions of radioactive elements cause air pollution.

Q70. Which industry has particularly lead to the yellowing of the marble of the Taj Mahal?

Solution

Soot given out from the Mathura oil refinery has lead to the yellowing of the Taj Mahal marble.

Q71. The Ganga Action Plan was launched in 1896.

• 1) False
• 2) True

Solution

The Ganga Action Plan was launched in 1986.

Q72. Expand LPG and CNG.

Solution

CNG - Compressed Natural Gas LPG - Liquefied Petroleum Gas

Q73. Emission of radioactive elements does not affect the air.

• 1) True
• 2) False

Solution

Emissions of radioactive elements cause air pollution.

Q74. List the characteristics of potable water.

Solution

Free from disease-causing germs and harmful chemicals Transparent, colourless and odourless Contains sufficient amount of dissolved oxygen and salts 

Q75. Sulphur dioxide and nitrogen dioxide rise high and combine with the ozone depleting it.

• 1) False
• 2) True

Solution

Sulphur dioxide and nitrogen dioxide are responsible for acid rains and not ozone depletion.

Q76. Portable water needs to be transparent, colourless and odourless.

• 1) False
• 2) True

Solution

True

Q77. CO₂ helps in the retention of heat.

• 1) False
• 2) True

Solution

True

Q78. Complete burning of fossil fuels is the major source of CO_2­ in the atmosphere.

• 1) False
• 2) True

Solution

Incomplete burning of fossil fuels is responsible for release of CO.

Q79. Potassium permanganate can be used as a disinfectant to purify water.

• 1) True
• 2) False

Solution

True

Q80. (i) What is Marble cancer? (ii) Name the poisonous gases which are emitted by the oil refineries and other industries in and around Taj Mahal that cause acid rain.

Solution

(i) Corrosion of marble due to acid rain is called marble cancer. (ii) Sulphur dioxide and nitrogen dioxide are the poisonous gases produced.

Q81. Increase in the population of decomposing bacteria in a water body kills the aquatic life because of

• 1) Lack of oxygen
• 2) Excess of oxygen
• 3) Lack of carbon dioxide
• 4) Excess of nitrogen

Solution

Decomposing bacteria feed on the dead and decomposing organic matter in the water and reduce the amount of oxygen in the water, thus killing most of the aquatic life.

Q82. At what temperature are microorganisms present in water killed?

Solution

Most microbes found in water are killed at a temperature of 100^oC, i.e. the boiling point of water.

Q83. What are the major sources of organic matter entering the water bodies as a pollutant?

Solution

The waste water released by factories and industries and the fertilizer run offs from agricultural fields is rich in organic matter. These when dumped in the water bodies pollute the water.

Q84. Burning of garbage increases the levels of CO₂ in the atmosphere.

• 1) True
• 2) False

Solution

True

Q85. (i) What happens when amount of CO₂ rise in atmosphere and become excessive? (ii) Which gas is mainly responsible for the green house effect?

Solution

(i) Rising amount of CO₂ causes more heat rays coming from the sun to be trapped in the atmosphere. This result in excessive heating of earth's atmosphere, therefore, temperature rises. This causes global warming. (ii)CO₂

Q86. Acid rains are responsible for only water pollution.

• 1) False
• 2) True

Solution

Acid rains are responsible for both soil and water pollution.

Q87. What is shown in the following pictures?

Solution

First figure shows clear water with good light penetration and less algal growth. Second figure shows polluted water with less light penetration and high algal growth.

Q88. Acid rains are responsible for only water pollution.

• 1) True
• 2) False

Solution

Acid rains are responsible for both soil and water pollution.

Q89. DDT stands for dichlorodiphenoltrichloromethane.

• 1) False
• 2) True

Solution

DDT stands for dichlorodiphenyltrichloroethane.

Q90. Fertiliser waste dumped into rivers is a cause for algal blooms.

• 1) False
• 2) True

Solution

True

Q91. List 5 ways for conservation of water.

Solution

Fix leaks and dripping taps. Leaking taps at home, school or any other place waste a lot of water. Do not leave the tap open while applying soap or brushing your teeth. Use a bucket to have a bath instead of a shower. One should make proper use of water in households. Use only the required amount of water. Mopping the floor instead of washing is another way of saving water. Use of a hosepipe to wash a car consumes a lot of water. Instead, use a bucketful of water to wash your car. Do not throw away water which is used for washing vegetables, dals and cleaning utensils. Instead, use it for watering plants. One can also collect rainwater and use it for different purposes such as watering of plants, cleaning the floor etc. One can avoid wastage of water by recycling it. (Any Five)

Q92. During the last three decades, the temperature of the Earth’s atmosphere has increased by 5°C.

• 1) False
• 2) True

Solution

During the last three decades, the temperature of the Earth’s atmosphere has increased by 0.5°C.

Q93. Which form of petrol is sold in the Taj zone?

Solution

Only unleaded petrol is sold in the Taj zone, as it is less polluting than leaded petrol.

Q94. Portable water needs to be transparent, colourless and odourless.

• 1) False
• 2) True

Solution

True

Q95. Is a UV filter sufficient to purify water and make it fit for consumption?

Solution

No, an ultraviolet filter only uses ultraviolet light, which kills microorganisms. A UV filter needs to be supplemented with a canister filter in order to make the water free from particulate and suspended materials for it to be fit for consumption.

Q96. A dripping tap can cause a loss of up to 72 litres of water per day.

• 1) False
• 2) True

Solution

True

Q97. DDT stands for dichlorodiphenoltrichloromethane.

• 1) True
• 2) False

Solution

DDT stands for dichlorodiphenyltrichloroethane.

Q98. Name a human disease which is a result of the biomagnification of mercury.

Solution

The disease caused by the biomagnification of mercury is known as Minamata disease.

Q99. Dysentery is a waterborne disease.

• 1) False
• 2) True

Solution

True

Q100. Which is the most tragic radioactive accident in the history of mankind?

Solution

The Chernobyl nuclear accident is the most tragic radioactive accident in the history of mankind.

Q101. According to the Ganga Action Plan, how is river water cleaned?

Solution

The polluted water of the Ganga is cleaned by intercepting and diverting waste water to sewage treatment plants instead of letting it flow directly into the river.

Q102. Acid rain is a cause of water pollution.

• 1) False
• 2) True

Solution

Acid rain is a cause of air pollution.

Q103. Mining activities release particulate pollutants in the air.

• 1) False
• 2) True

Solution

True