Question 11 : The normal dose of chlorine during break point chlorination is
1. 0.5-1ppm
2. 0.1-0.2ppm
3. 3-7ppm
4. 1-2ppm
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Question 12 : Boiling of water is a _____ method of disinfection.
1. Physical
2. Chemical
3. Mechanical
4. Electrical
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Question 13 : Which color is formed when orthotolidine is oxidized by chlorine?
1. Yellow
2. Orange
3. Green
4. Blue
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Question 14 : The contact time for disinfection by free chlorine is
1. 20 minutes
2. 30 minutes
3. 40 minutes
4. 60minutes
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Question 15 : The water is free from oxidizable materials. What is the dosage of ozone required?
1. 0.01ppm
2. 0.1-0.2ppm
3. 0.2-0.3ppm
4. 0.4-0.5ppm
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Question 16 : The number of organisms destroyed is equal to the number of organisms remaining at time t=
1. 0
2. 1
3. 2
4. 10
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Question 17 : At what pH, the dissociation of hypoiodous acid takes place?
1. 1
2. 2
3. 3
4. 4
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Question 18 : Which of the following is a chemical method of disinfection?
1. Disinfection by heat
2. Disinfection by light
3. Metal ions
4. Metal ions, Alkalis and acids
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Question 19 : Which of the following is the expression of Chicks law?
1. Dy/Dt = k (N – y)
2. Dy/Dt = k/(N – y)
3. Dy/Dt = k (N + y)
4. Dy/Dt = k (N * y)
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Question 20 : a HIO + b OH- <=> HIO₃ + b H₂O + b I^–. What are the values of a and b respectively in the above equation?
1. 1, 2
2. 1, 3
3. 3, 2
4. 3, 1
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