A. 0°C
B. 15°C
C. 20°C
D. 25°C
Related Mcqs:
- Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to_______________?
A. Initial demand
B. First stage demand
C. Carbonaceous demand
D. All of these - If a 2% solution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is_________________?
A. 100 mg/l
B. 200 mg/l
C. 300 mg/l
D. 400 mg/l - If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21°C, B.O.D. of the sewage is_____________________?
A. 50 ppm
B. 100 ppm
C. 150 ppm
D. 200 ppm - If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is_________________?
A. 50 mg/l
B. 100 mg/l
C. 150 mg/l
D. 250 mg/l - If 2% solution of a sewage sample is incubated for 5 days at 20°C and depletion of oxygen was found to be 5 ppm, B.O.D. of the sewage is____________________?
A. 200 ppm
B. 225 ppm
C. 250 ppm
D. None of these - To test chemical oxygen demand (C.O.D.) of sewage, organic matter is oxidised by potassium dichromate in the presence of_______________?
A. Hydrochloric acid
B. Sulphuric acid
C. Nitric acid
D. Citric acid - For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed________________?
A. 3 ppm
B. 4 ppm
C. 5 ppm
D. 10 ppm - The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known_________________?
A. Bio-Chemical Oxygen Demand (B.O.D.)
B. Dissolved Oxygen (D.O.)
C. Chemical Oxygen Demand (C.O.D.)
D. None of these - The pH value of sewage is determined with the help of_________________?
A. Imhoff Cone
B. Turbid meter
C. Potentiometer
D. None of these - The porosity of sediments in sewer pipes, is usually taken as___________________?
A. 0.010
B. 0.011
C. 0.012
D. 0.013
