Water

1. The quantity of water available for the actual use is _________
a) 10%
b) 5%
c) 0.5%
d) 1%

Answer: c
Explanation: The quantity of water available on the earth’s crust is about 80% and the quantity of water available for actual use that is in the form of rivers, tanks is about 0.5%.

2. __________ of water is struck in underground which is not accessibly.
a) 1%
b) 2%
c) 3%
d) 4%

Answer: a
Explanation: 96% of the water is struck in the forms of oceans which is too saline to use it directly and 2% is polar ice caps and glaciers and 1% is under ground water.

3. ___________ is the purest form of the water obtained by natural distillation.
a) Under ground water
b) Sea water
c) River water
d) Rain water

Answer: d
Explanation: Rain water is the purest form of the water obtained by natural distillation. Some part of the rain water penetrates into the ground and there it will be stored.

4. Lake water contains more __________ due to the biological oxidation of the organic matter.
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Carbon monoxide

Answer: b
Explanation: Lake Water contains more amount of carbon dioxide due to the biological oxidation of the organic matter present at the bottom of the lake.

5. The colour and odour of the natural water is due to the presence of the ___________
a) Dissolved organic matter
b) Mud
c) Leaves
d) Other dust particles

Answer: a
Explanation: The colour and odour of the natural water is due to the presence of the dissolved organic matter. Dissolved gases like nitrogen, oxygen and carbondioxide are present in lake water.

6. Deep well water possess the rotten egg smell due to the dissolved ________
a) Sulphide
b) Sulphurous acid
c) Hydrogen sulphide
d) Hydrogen peroxide

Answer: c
Explanation: Deep well water possesses the rotten egg smell due to the dissolved hydrogen sulphide. The underground water is colourless and odourless.

7. Well water in wells located in the areas of oil and gases will contain __________
a) Ethane
b) Methane
c) Carbon
d) Nitrogen

Answer: b
Explanation: Well water in wells located in the areas of oil and gases will contain methane gas. When rain water falls on earth and flows on the earth and becomes impure.

8. Surface water appears turbid due to the presence of the __________ which remains suspended in the water.
a) Impurities
b) Oxygen
c) Nitrogen
d) Water plants

Answer: a
Explanation: Surface water appears turbid due to the presence of the impurities which remains suspended in the water. The dissolved gases make the water into bad odour.

9. Which of the following is the suspended impurity?
a) Iron hydroxide
b) Dust
c) Mud
d) Nitrogen

Answer: a
Explanation: The nitrogen is the dissolved impurity. The suspended impurities are iron hydroxide, silica are the inorganic impurities which decomposes the organic impurities.

10. The suspended impurities is negligible due to the filtering action of __________
a) Water plants
b) Dissolved impurities
c) Soil
d) Dissolved gases

Answer: c
Explanation: The suspended impurities are negligible due to the filtering action of the soil. The soil filters all the suspended impurities like silica and iron hydroxide.

11. How many types of absorbed impurities in water are there mainly?
a) 2
b) 3
c) 4
d) 5

Answer: c
Explanation: There are four types of impurities in water are there. They are suspended impurities, dissolved gases, dissolved mineral salts and bacterial impurities.

12. In dissolved mineral salts ___________ gets converted into the bicarbonates by the action of carbondioxide by water.
a) Carbonate of calcium
b) Carbonates of magnesium
c) Carbonates of calcium and magnesium
d) Neither carbonates of calcium nor magnesium

Answer: c
Explanation: In dissolved mineral salts, the carbonates of calcium and magnesium get converted into the bicarbonates by the action of the carbondioxide by water.

13. ___________ water contains more soluble salts than the surface water.
a) Sea water
b) Rain water
c) Underground water
d) Tank water

Answer: c
Explanation: Sea water and tank water comes under the surface water and the under ground water contains more soluble salts than the surface water.

14. Amino acids comes under _________ impurity.
a) Dissolved impurity
b) Colloidal impurity
c) Dissolved gases
d) Bacterial impurities

Answer: b
Explanation: Amino acids comes under the colloidal impurities. All the gases like nitrogen, oxygen and carbondioxide comes under the dissolved gases.

15. Chemical composition of the lake water is _________
a) Constant
b) Not constant
c) Some times constant
d) Cannot be determined

Answer: a
Explanation: Chemical composition of lakes is constant. It has a high quantity of organic matter and lesser quantity dissolved minerals.

16. Soaps can be defined as the soap consuming capacity of the water sample.
a) True
b) False

Answer: a
Explanation: Soaps are defined as the soap consuming capacity of the water. Soaps are sodium salts of fatty acids like oleic acid and stearic acid.

17. The soft water contains the hardness of about ____________
a) 0-45ppm
b) 0-55ppm
c) 0-65ppm
d) 0-75ppm

Answer: d
Explanation: The soft water contains the hardness of about 0-75ppm. The hardness of water is mainly due to the salts of calcium and magnesium.

18. The hardness of moderately hard water is about _____________
a) 75-150ppm
b) 75-120ppm
c) 75-130ppm
d) 75-100ppm

Answer: a
Explanation: The hardness of CaCO3 of moderately hard water is about 75-150ppm. The hardness of the water can be calculated from amount of calcium and magnesium ions present in water along with bicarbonates, sulphates.

19. The very hard water has the hardness of CaCO3 is given by ___________
a) 100-200ppm
b) 100-300ppm
c) 200-300ppm
d) Above 300ppm

Answer: c
Explanation: The very hard water has the hardness of CaCO3 is given about above 300ppm. The hard water is having the hardness of CaCO3 is given by 150-300ppm.

20. The PH value of the drinking water is about _________
a) 6.5-8.5
b) 5.5-6.5
c) 4.5-5.5
d) 3.5-4.5

Answer: a
Explanation: The PH value of the drinking water is about 6.5 to 8.5. The odour of the drinking water is unobjectionable but the drinking water is generally having no odour.

21. The drinking water can have the magnesium limit about ____________
a) 10-150ppm
b) 20-150ppm
c) 30-150ppm
d) 40-150ppm

Answer: c
Explanation: The drinking water can have the magnesium limit about 30-150ppm. The calcium in the drinking water can be about 75-200ppm.

22. The chloride in drinking water range can be about ___________
a) 200-600ppm
b) 300-600ppm
c) 400-600ppm
d) 500-600ppm

Answer: a
Explanation: The chloride in drinking water range can be about 200-600ppm. The nitrate is about the range of 45ppm in drinking water.

23. The iron is about the range in drinking water is _________
a) 1-1.5ppm
b) 0.01-0.1ppm
c) 1-1.1ppm
d) 0.1-1ppm

Answer: d
Explanation: The iron is about the range in drinking water is 0.1-1.0ppm. The magnesium is about the range of 30-150ppm in drinking water.

24. The phosphate is about the range of __________ in drinking water.
a) 5-10ppm
b) 10-15ppm
c) 15-20ppm
d) 20-25ppm

Answer: b
Explanation: The phosphate is about the range of 10-15ppm in drinking water. The sulphate in drinking water is about 200-400ppm.

25. The organic matter in drinking water must be about _________
a) 0.2-1.0ppm
b) 1.0-2.0ppm
c) 2.0-3.0ppm
d) 3.0-4.0ppm

Answer: a
Explanation: The organic matter in drinking water must be about 0.2-1.0ppm. The phosphate is also low that is about 10-15ppm.

26. In _____________ when the eater is heated then the soluble salts turns into insoluble ones and removed by filtration.
a) Temporary hardness
b) Permanent hardness
c) Non-carbonate
d) Non-alkaline

Answer: a
Explanation: The hardness in the temporary hard water can be removed by heating and filtrating the insoluble salts.

27. Which of the following does not cause the permanent hardness in water?
a) Nitrates
b) Sulphates
c) Chlorides
d) Bicarbonates

Answer: d
Explanation: The bicarbonates of the calcium and magnesium cause the temporary hardness and the sulphides, nitrates and the chlorides cause permanent hardness.

28. The total hardness can be given by _________
a) Temporary + permanent hardness
b) Temporary – permanent hardness
c) Temporary * permanent hardness
d) Temporary/permanent hardness

Answer: a
Explanation: The sum of the temporary and permanent hardness of the water gives the total hardness of the water.

29. Which of the following process does not remove the permanent hardness of water?
a) Lime-soda
b) Ion exchange process
c) Zeolite process
d) Heating

Answer: c
Explanation: Heating of the water removes the temporary hardness and the permanent hardness is removed by the zeolite process, lime soda process and the ion exchange method.

30. All carbonate and bicarbonates are _________
a) Alkaline
b) Acidic
c) Highly acidic
d) Neutral

Answer: a
Explanation: All the carbonates and bicarbonates are alkaline in nature. So, the hardness due to them is called carbonate hardness or alkaline hardness.

31. The cost of the lime soda process is _________
a) Less
b) High
c) Very high
d) Moderate

Answer: a
Explanation: The cost of the lime soda process is less and the operational cost of the lime soda process is high.

32. ___________ can be used for the turbid water.
a) Soap titration process
b) Zeolite process
c) Ion exchange process
d) Lime soda process

Answer: d
Explanation: Lime soda process can be used for the turbid water. The lime soda process removes the hardness of the water steps wise by treating with different chemicals.

33. Hardness of the water in the lime soda process is reduced to __________
a) 10-15ppm
b) 15-30ppm
c) 30-35ppm
d) 35-40ppm

Answer: b
Explanation: Hardness of the water in the lime soda process is reduced to 15-30ppm. The lime soda process involves the conversion of the soluble complexes into the insoluble precipitates.

34. Total dissolved solids in the lime soda process is _________
a) Reduced
b) Not reduced
c) Remains same
d) Slightly reduced

Answer: a
Explanation: Total dissolved solids in the lime soda process is reduced. It really works well for eliminating every complex element that cause the hardness of the water.

35. For avoiding the reduction of the residual hardness, incomplete precipitation and slow reaction, The reaction is carried out at __________ temperature.
a) 30-40oC
b) 40-50oC
c) 50-60oC
d) 60-70oC

Answer: c
Explanation: For avoiding the reduction of the residual hardness, incomplete precipitation and slow reaction, The reaction is carried out at 50-60oC temperature.

36. Lime soda process removes _________ from the water.
a) Minerals
b) Mineral acids
c) Mineral alkaline
d) Mineral complexes

Answer: b
Explanation: Lime soda process removes the mineral acids from the water. The cold soda lime, hot soda lime and continuous soda lime process are other processes to remove the hardness.

37. Batch process is only used for removing the hardness of the water on _________
a) Small scale
b) Large scale
c) Industrial purposes
d) Irrigation purposes

Answer: a
Explanation: Batch process is only used for removing the hardness of the small scale. The Continuous soda lime process is used for the industrial purposes.

38. The amount of coagulate if added in the hot lime soda process is __________
a) High
b) Low
c) Very high
d) Very low

Answer: d
Explanation: The amount of coagulate if added in the hot lime soda process is very low. The chemical reaction takes place faster and precipitation takes place faster.

39. The final hardness of the water after treating by the hot lime soda process is about __________
a) 10-15ppm
b) 15-20ppm
c) 20-25ppm
d) 25-30ppm

Answer: c
Explanation: The final hardness of the water after treating by the hot lime soda process is about the 20-25ppm. In very less time the water is treated in this method.

40. Due to heating at high temperature in the hot lime soda process reduces the __________
a) Time for treating
b) Energy
c) Corrosion of boiler
d) Cost

Answer: c
Explanation: Due to heating at high temperature in the hot lime soda process reduces the corrosion of boilers. The heating is done to remove the dissolved gases in the water.

41. Lime soda process does not involve steps.
a) True
b) False

Answer: b
Explanation: Lime soda process involves steps like filtration, settling of precipitates, coagulation and removal of sludge.

42. In hot lime soda process, the bacteria in water is reduced to the minimum due to the _________
a) High temperature
b) Faster reactions
c) Slow reactions
d) Low temperature

Answer: a
Explanation: In hot lime soda process the bacteria count in water is reduced to the minimum due to the high temperatures that are applied to the water during the process.

43. In batch process, when the tank gets filled then it indicates that ____________
a) To stir more
b) Softening is completed
c) To add the catalyst
d) To add the lime

Answer: b
Explanation: In batch process, when the tank gets filled then it indicates that the softening of the water is completed. Two tanks are used for construction in the batch process.

44. Reagent used in the lime soda process is _______
a) Regenerated
b) Not regenerated
c) Regenerated depending on the hardness
d) Regenerated some times

Answer: b
Explanation: Reagent used in the lime soda process is can not be regenerated. The high temperatures are applied in this process.

45. In lime soda process, the change in the hardness of the water needs ________
a) Change in dose of lime
b) Change in dose of soda
c) Change in dose of lime and soda
d) Change in dose either lime or soda

Answer: c
Explanation: In lime soda process, the change in the hardness of the water needs the change in the dose of the lime and soda.

46. Ion exchange process is also called as ___________
a) Permutit’s process
b) Demineralization
c) Zeolite process
d) Lime soda process

Answer: b
Explanation: Ion exchange process is also called as the demineralization. The zeolite process is otherwise called as the ion exchange process.

47. The operational cost of the ion exchange process is __________
a) High
b) Low
c) Very high
d) Very low

Answer: b
Explanation: The capital cost of the ion exchange process is very high. The operational cost of the ion exchange process is about low.

48. The hardness in the ion exchange process is reduced to ___________
a) 0-1ppm
b) 0-2ppm
c) 0-3ppm
d) 0-4ppm

Answer: b
Explanation: The hardness of the ion exchange process is reduced to 0 to 2ppm. It is a very effective method to reduce the hardness of the water.

49. The total __________ are removed completely in the ion exchange process.
a) Dissolved gases
b) Dissolved solids
c) Dissolved solvents
d) Dissolved other impurities

Answer: b
Explanation: The total dissolved solids are removed completely in the ion exchange process. In lime soda process, the total dissolved solids are reduced only.

50. In ion exchange process, the iron and manganese ions are removed from the water.
a) True
b) False

Answer: a
Explanation: In ion exchange process, not only iron and manganese ions are removed from the water but also all the cations are removed.

51. Water softened during __________ method will be ideal in boilers.
a) Zeolite method
b) Lime soda method
c) Demineralisation method
d) Permutit’s process

Answer: b
Explanation: Water softened during the demineralisation method is completely free from all the impurities and flaws. So, the water after the softening by this method will be ideal for boilers.

52. Ion exchange process is the clean process because it has ___________
a) Sludge formation
b) No sludge formation
c) Little sludge is formed
d) Other precipitates are formed

Answer: b
Explanation: In ion exchange process, there is no formation of sludge. So, it is called as the clean process.

53. The regeneration of acids and alkalis in ion exchange process is __________
a) Cheaper
b) Costlier
c) Time taking
d) Hard process

Answer: b
Explanation: The one of the disadvantages of the ion exchange process is the regeneration of the acids and alkalis in ion exchange process is costlier.

54. In ion exchange process, the cation exchange resin is generated by passing ____________
a) Acids
b) Dilute acids
c) Alkalis
d) Dilute alkalis

Answer: b
Explanation: In ion exchange process, the cation exchange resin is generated by passing the dilute acids. The anion exchange resin is generated by passing alkali.

55. In the case of the zeolites, ion exchange process do not function properly because of the __________
a) Turbidity
b) Suspended matter
c) Turbidity and suspended matter
d) Neither turbidity nor suspended matter

Answer: c
Explanation: In case of zeolites, ion exchange process do not function properly because of the turbidity and suspended matter as they send to cover the surface of the resin.

57. The initial equipment in the ion exchange process is ___________
a) More
b) Less
c) Very less
d) Very high

Answer: a
Explanation: The initial equipment in the ion exchange process is more. Continuous supply of softened water can be made available by providing storage facilities.

58. The residual hardness after the treatment of water is about __________
a) 1 ppm
b) Less than 1ppm
c) 2 ppm
d) Less than 2pmm

Answer: d
Explanation: The residual hardness after the treatment of the water is about less than 2ppm. So, they are suitable for the high pressure boilers.

59. The continuous supply of soft water can be provided by having ____________
a) Storage facilities
b) Required amount of ppm
c) High pressure boilers
d) 1ppm

Answer: a
Explanation: The continuous supply of soft water can be provided by having storage facilities and also two columns of each resin.

60. The cost of the resins used in the ion exchange process is _________
a) High
b) Low
c) Moderate
d) Depends on water

Answer: a
Explanation: The cost of the resins used in the ion exchange process is high and the regeneration of the resins in also a costly process.

61. The mineral free water is not used in __________
a) Pharmaceuticals
b) Cosmetics
c) Explosives
d) Drinking

Answer: d
Explanation: In drinking water some minerals must be present. In pharmaceuticals, cosmetics, explosives and in other manufacturing processes, the mineral free water is used.

62. In biological oxidation process, depending on the organic load, the oxidation takes place ___________
a) 1-4Hours
b) 4-8Hours
c) 8-16Hours
d) 16-20Hours

Answer: b
Explanation: In biological oxidation process, depending on the organic load, the oxidation process takes place up to 4 to 8 hours. Organic impurities are reduced by the biological oxidation process by micro organisms.

63. All impurities are oxidised into the _________ and ___________ in the biological oxidation process.
a) Oxygen and water
b) Carbondioxide and water
c) Nitrogen and water
d) Chlorine an water

Answer: b
Explanation: All impurities are oxidised into the carbondioxide and water in the biological oxidation process. The sludge formed in this process will be settled down quickly and gives clear supernatant.

64. The water after removing of sludge in the biological oxidation process is treated with ____________
a) Chlorine
b) Bromine
c) Fluorine
d) Iodine

Answer: a
Explanation: The water after removing of sludge in the biological oxidation process is treated with the chlorine or bleaching powder to make it more safe and let it into surface water.

65. Trickling filter method is ___________ than the activated sludge process.
a) Fast
b) Slow
c) Very fast
d) Moderate

Answer: b
Explanation: Trickling filter method is slow process than that of the activated sludge process. This process is convenient and cheaper process than the activated sludge process.

66. The depth of the rectangular circular tanks in the trickling filters method is having the depth of ____________
a) 4m
b) 3m
c) 2m
d) 1m

Answer: c
Explanation: The depth of the rectangular circular tanks in the trickling filters method is having the depth of the 2 metres packed with broken stone pieces or coal etc.

67. Periodic cleaning is used to _________
a) Increase efficiency
b) Decrease efficiency
c) Increase pressure
d) Decrease dissolved oxygen

Answer: a
Explanation: Periodic cleaning is necessary to remove excess sludge in the water. So, it is useful to increase the efficiency of the process.

68. In the trickling filter process, the _________ build up and they block the passage.
a) Sludge formed
b) Dissolved impurities
c) Dissolved solids
d) Micro organisms

Answer: d
Explanation: The micro organism built up and they block the passage and then the rate of flow drops considerably.

69. Dried sludge can be used as _________
a) Fertilizer
b) Pesticide
c) Reagent
d) Medicine

Answer: a
Explanation: Dried sludge can be used as the fertilizer. It is one of the main advantages. The sludge is de watered by the filtration in sand beds.

70. The unpleasant odour of the water is due to presence of the __________
a) Nitrogen
b) Bismuth
c) Phenols
d) Dissolved oxygen

Answer: c
Explanation: The unpleasant odour of the water is due to the presence of the phenols, hydrogen sulphides, chlorine and organic sulphur compounds.

71. __________ imparts peculiar odour to the water.
a) Decaying organic matter
b) Detergents
c) Phenols
d) Dissolved oxygen

Answer: b
Explanation: The bad odour of water is due to the phenols, decaying organic matter and phenols. The peculiar odour is due to the detergents and pesticides.

72. Reacting the water with _________ removes the odour due to the phenols.
a) KMnO4
b) MnO4
c) Potassium
d) Magnesium

Answer: a
Explanation: The chlorination of water and reacting the water with the potassium permanganate removes the odour of water due to phenols.

73. The treatment of water with _________ improves the taste of water.
a) Oxygen
b) Chlorine
c) KMnO4
d) Ozone

Answer: d
Explanation: The treatment of water with the ozone improves the taste of the water and the bed of activated carbon removes the colour.

74. How many methods of removing the radio active impurities are there?
a) 2
b) 3
c) 3
d) 4

Answer: a
Explanation: There are two types of methods. They are: By absorbing the radio active elements by using suitable absorbent. Allowing of such periods at which it separates from water.

75. ___________ poisoning water in Japan is from fishes.
a) Bismuth
b) Arsenic
c) Antimony
d) Palladium

Answer: b
Explanation: The arsenic poisoning water in Japan is from fishes where the industrial effluent was going into the sea containing arsenic.

76. Fishes can store more quantity of ___________ in their bodies.
a) Mercury
b) Bismuth
c) Palladium
d) Chlorine

77. Waste water released from _________ are not the sources of bacteria.
a) Sanitaria
b) Municipalities
c) Tanning
d) Industries

Answer: d
Explanation: Waste water released from the sanitarias, municipalities, tanning and slaughtering plants are the sources of the bacteria.

78. Bacteria and micro organisms present in the water will cause _________ in human and animals.
a) Indigestion
b) Intestinal tract
c) Brain tumour
d) Cancer

Answer: b
Explanation: Bacteria and micro organisms present in the water will cause intestinal tract. The infected individual has the intestinal discharge containing the billions of pathogens.

79. Infectious hepatitis is caused by ___________
a) Bacteria
b) Viruses
c) Protozoa
d) Helminth

Answer: b
Explanation: The infectious hepatitis is caused by viruses. The viruses in water also cause the poliomyelitis disease.

80. Amoebic dysentery is caused by ___________
a) Viruses
b) Bacteria
c) Helminth
d) Protozoa

Answer: d
Explanation: Amoebic dysentery is caused by the protozoa present in the drinking water. In this disease, the water content from the body is lost and the person will become weak.

81. Bacteria in water causes ________
a) Malaria
b) Typhoid
c) Dengue
d) Chicken guinea

Answer: b
Explanation: Bacteria in water causes the typhoid. This includes a high fever for the person. Bacteria in water also cause the cholera.

82. Helminth in the water causes __________
a) Hook worm
b) Amoebic dysentery
c) Cholera
d) Typhoid

Answer: a
Explanation: Helminth in the water causes the hook worm and also the guinea worm in the person. Amoebic dysentery is caused by the protozoa and cholera and typhoid is caused by the bacteria in water.

83. The ____________ is an important requirement of the aquatic life.
a) Dissolved nitrogen
b) Dissolved chlorine
c) Dissolved oxygen
d) Dissolved methane

Answer: c
Explanation: The dissolved oxygen is an important requirement of the aquatic life. They take oxygen from the water to survive.

84. The optimum value in natural water is ________
a) 2-4ppm
b) 4-7ppm
c) 4-6ppm
d) 2-7ppm

Answer: c
Explanation: The optimum value in natural water is about 4-6ppm. Decrease in the quantity of the dissolved water indicates the pollution of water.

85. What is the full form of BOD?
a) Biochemical oxygen demand
b) Biological oxygen demand
c) Biometric oxygen deep water
d) Biological oxygen deep water

86. COD is the short form of the chemical oxygen demand.
a) True
b) False

Answer: a
Explanation: COD is the short form of the chemical oxygen demand. The total organic content present in water is determined in another parameter called COD.

87. The disappearance of the plants and animals is due to the _________ in water.
a) Nitrogen depletion
b) Chlorine depletion
c) Oxygen depletion
d) Ozone depletion

Answer: c
Explanation: The disappearance of the plants and animals is due to the depletion of the oxygen in the water. Micro organisms mainly bacteria uses the organic matter in water as food.

88. The decomposition of the matter produces into ___________ and in presence of ____________
a) Carbondioxide and oxygen
b) Oxygen and nitrogen
c) Nitrogen and carbondioxide
d) Nitrogen and chlorine

Answer: a
Explanation: The decomposition of the matter produces into carbondioxide and in the presence of oxygen. Oxygen is taken from the water.

89. The organic matter present in the water is of __________ types.
a) Two
b) Three
c) Four
d) Five

Answer: a
Explanation: The organic matter present in the water is of two types. They are biologically oxidisable and biologically inert.

90. The BOD value of the domestic sewage is about __________
a) 160
b) 161
c) 166
d) 168

Answer: c
Explanation: The BOD value of domestic sewage is about 166ppm. Total quantity of organic matter utilised is called as the BOD.

91. Non hazardous organic wastes from the sewage is to be separated from the ___________
a) Toxic industrial wastes
b) Bacteria
c) Helminth
d) Protozoa

Answer: a
Explanation: Non hazardous organic wastes from the sewage is to be separated from the toxic industrial wastes. The entry of the harmful things into water must be prevented.

92. Domestic water treatment is carried out under __________ conditions.
a) Aerobic
b) Anaerobic
c) Cannot be known
d) Depends on the pollution level of water

Answer: a
Explanation: Domestic water treatment is carried out in presence of the oxygen. The oxygen is taken from the water. So, it is aerobic process.

93. The BOD value of industrial waste must be about _________
a) 100
b) 200
c) 300
d) 400

Answer: b
Explanation: The BOD value of the industrial waste must be about the 200. The BOD value of the paper industry waste is about 370.

94. The BOD value of the food industry is about ___________
a) 742
b) 743
c) 744
d) 745

Answer: d
Explanation: The BOD value of the food industry is about 745. This value is higher than that of the normal limits.

95. In domestic water treatment, after the primary treatment _________ is done.
a) Screening
b) Sedimentation
c) Aerobic process
d) Anaerobic process

Answer: a
Explanation: In domestic water treatment, after the primary treatment of screening is done. Later sedimentation process is done.

96. In the domestic water process, when air is sent during the active sludge, then _________ released.
a) Oxygen
b) Carbondioxide
c) Nitrogen
d) Chlorine

Answer: b
Explanation: When the air is sent during the active sludge, then the carbondioxide is released in domestic water process.

97. In final step of the domestic water process, the effluent contain ___________ BOD.
a) 10ppm
b) 15ppm
c) 20ppm
d) 25ppm

Answer: d
Explanation: The effluent obtained in the final step of the domestic water process contains ammonia ion and having the 25ppm.

98. Aerobic process is also called as ___________
a) Activated sludge process
b) Sludge thickening process
c) Sedimentation
d) Screening

Answer: a
Explanation: Aerobic process is also called as the activated sludge process. The sludge thickening, sedimentation and screening are the steps involved in the domestic water treatment.

99. By aerobic process _________ of biodegradable water is converted into the biomass.
a) 10%
b) 30%
c) 50%
d) 75%

Answer: c
Explanation: By aerobic process the 50% of the biodegradable water is converted into the biomass and the remaining 50% into carbondioxide.

11. In anaerobic treatment the organic acid and alcohol is undergone into ___________ process.
a) Sedimentation
b) Screening
c) Catalysis
d) Fermentation

Answer: d
Explanation: In anaerobic treatment, the organic acid and alcohol is undergone into fermentation at 35oC and the ppm of 5 to 6.

101. When two solutions of the different concentration are separated by the semi permeable membrane then the solvent flows from low to higher concentration is called osmosis.
a) True
b) False

Answer: a
Explanation: Always the energy flows from lower to higher concentration. When two solutions of the different concentration is separated by the semi permeable membrane then the solvent flows from low to higher concentration is called osmosis.

102. Which of the following method is not the method of desalination?
a) Reverse osmosis
b) Multi flash distillation
c) Electro dialysis
d) Smelting

Answer: d
Explanation: The reverse osmosis, multi flash distillation and electro dialysis are the methods of desalination and smelting is not the process of desalination.

103. The natural tendency of the water can be reversed by applying ________ to the salty water part.
a) Low pressure
b) High pressure
c) Low temperature
d) High temperature

Answer: b
Explanation: The natural tendency of the water can be reversed by applying the high pressure with a piston to the salty part of the water.

104. In reverse osmosis, the water flows from __________ concentration to ___________ concentration.
a) Low, high
b) High, low
c) High, moderate
d) Moderate, low

Answer: a
Explanation: In reverse osmosis, the water flows from the lower to higher concentration. In osmosis the water flows from the higher to lower concentration.

105. The semi permeable membranes used in the reverse osmosis is _________
a) Cellulose
b) Glucose
c) Cellulose acetate
d) Glucose acetate

Answer: c
Explanation: The semi permeable membrane used in reverse osmosis is cellulose acetate and cellulose butyrate etc.

106. By ultra filtration aldrin can be removed by _________
a) 100%
b) 99%
c) 98%
d) 97%

Answer: b
Explanation: By ultra filtration process, many micro organisms can be removed by reacting the industrial waste with activated charcoal. Aldrin can be removed by 99%.

107. __________ co polymer can remove the chlorinated pesticides.
a) Styrene di vinyl benzene
b) Styrene
c) Benzoyl peroxide
d) Phenol

Answer: a
Explanation: The styrene di vinyl benzene can remove the chlorinated pesticides by absorption at the surface.

108. Increase in the BOD value in the water indicates ___________
a) Decrease in pollution
b) Increase in pollution
c) Pollution is independent of BOD
d) Slight decrease in the BOD

Answer: b
Explanation: Increase in the value of the BOD in water indicates the increase in the water pollution.

109. The organic matter have the limit in water that is about __________
a) 0.2 to 1
b) 0.5 to 1
c) 1 to 2
d) 2 to 4

Answer: a
Explanation: The organic matter has the desired limit in water about 0.2 to 1 ppm. Increase in the value indicates the pollution.

110. In sewage the waste is about ___________
a) 0.01
b) 0.02
c) 0.03
d) 0.05

Answer: d
Explanation: Sewage contains 99.95% of water and 0.05% of the organic and municipal wastes. Strength of sewage is expressed in terms of BOD.