61. The percentage of chlorine in fresh bleaching powder is about
a) 10 to 15
b) 20 to 25
c) 30 to 35
d) 40 to 50
Ans:c
62. The treatment of water with bleaching powder is known as
a) prechlorination
b) super chlorination
c) dechlorination
d) hypochlorination
Ans:d
63. The suitable method for disinfection of swimming pool water is
a) ultra violet rays treatment
b) lime treatment
c) by using potassium permanganate
d) chlorination
Ans:a
64. Which of the following chemical compounds can be used for dechlorination of water ?
a) carbon dioxide
b) bleaching powder
c) sulphur dioxide
d) chloramines
Ans:c
65. In chlorination, with the rise in temperature of water, death rate of bacteria
a) increases
b) decreases
c) remains unaffected
d) none of the above
Ans:a
66. As compared to higher pH values, the contact period required for efficient chlorination at lower pH values is
a) smaller
b) larger
c) same
d) none of the above
Ans:a
67. Disinfection efficiency is
a) reduced at higher pH value of water
b) unaffected by pH value of water
c) increased at higher pH value of water
d) highest at pH value equal to 7
Ans:a
68. In lime-soda process
a) only carbonate hardness is removed
b) only non-carbonate hardness is re-moved
c) lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness
d) lime reduces the non-carbonate hard-ness and soda-ash removes the carbo¬nate hardness
Ans:c
69. The major disadvantage of lime soda process of water softening is that
a) it is unsuitable for turbid and acidic water
b) huge amount of precipitate is formed which creates a disposal problem
c) the effluent cannot be reduced to zero hardness
d) it is unsuitable for softening the water of excessive hardness
Ans:b
70. Which of the following compounds is widely used for algae control ?
a) sodium sulphate
b) copper sulphate
c) sodium chloride
d) calcium chloride
Ans:b
a) 10 to 15
b) 20 to 25
c) 30 to 35
d) 40 to 50
Ans:c
62. The treatment of water with bleaching powder is known as
a) prechlorination
b) super chlorination
c) dechlorination
d) hypochlorination
Ans:d
63. The suitable method for disinfection of swimming pool water is
a) ultra violet rays treatment
b) lime treatment
c) by using potassium permanganate
d) chlorination
Ans:a
64. Which of the following chemical compounds can be used for dechlorination of water ?
a) carbon dioxide
b) bleaching powder
c) sulphur dioxide
d) chloramines
Ans:c
65. In chlorination, with the rise in temperature of water, death rate of bacteria
a) increases
b) decreases
c) remains unaffected
d) none of the above
Ans:a
66. As compared to higher pH values, the contact period required for efficient chlorination at lower pH values is
a) smaller
b) larger
c) same
d) none of the above
Ans:a
67. Disinfection efficiency is
a) reduced at higher pH value of water
b) unaffected by pH value of water
c) increased at higher pH value of water
d) highest at pH value equal to 7
Ans:a
68. In lime-soda process
a) only carbonate hardness is removed
b) only non-carbonate hardness is re-moved
c) lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness
d) lime reduces the non-carbonate hard-ness and soda-ash removes the carbo¬nate hardness
Ans:c
69. The major disadvantage of lime soda process of water softening is that
a) it is unsuitable for turbid and acidic water
b) huge amount of precipitate is formed which creates a disposal problem
c) the effluent cannot be reduced to zero hardness
d) it is unsuitable for softening the water of excessive hardness
Ans:b
70. Which of the following compounds is widely used for algae control ?
a) sodium sulphate
b) copper sulphate
c) sodium chloride
d) calcium chloride
Ans:b
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