A. 5
B. 100
C. 250
D. 500
Related Mcqs:
- For existence of aquatic life in water, the dissolved oxygen content in it, should not be less than ______________ ppm?
A. 10000
B. 5
C. 500
D. 1000 - Pure oxygen is mixed with air to produce an enriched air containing 50 volume % of oxygen. The ratio of moles of air to oxygen used is_________________?
A. 1.72
B. 0.58
C. 0.5
D. 0.2 - Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by________________?
A. Natural aeration of water stream
B. Photosynthetic action of algae
C. Both A. & B.
D. Neither A. nor B. - Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N2 in contaminated air at which it acts as a natural asphyxiate is ≥ _____________ percent?
A. 84
B. 88
C. 80
D. 92 - A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0°C, 760 mm Hg) will be _____________ litres?
A. 448
B. 224
C. 22.4
D. Data insufficient; can’t be computed - Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favouring bacterial growth. A rise in water temperature by 10°C, doubles the toxic effects of _____________ present in it?
A. Coal ash
B. Potassium cyanide
C. Ortho-xylene
D. None of these - Maximum permissible turbidity in potable water is _____________ ppm?
A. 1
B. 10
C. 250
D. 1000 - TLV of lead for public sewer/waste water is about ______________ ppm?
A. 1
B. 25
C. 150
D. 650 - Maximum allowable concentration of CO2 in air for safe working is _____________ ppm (parts per million)?
A. 50
B. 1000
C. 2000
D. 5000 - Tolerable limit of nitrogen oxides in air is _____________ ppm?
A. 0.1
B. 1
C. 5
D. 25
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