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?

Related Mcqs:

1. Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in____________________?

   A. Coagulation and flocculation of colloids
   B. Oxidation of carbonaceous matter to CO2
   C. Nitrification or oxidation of ammonia derived from breakdown of nitrogenous organic matter
   to the nitrite and eventually to the nitrate
   D. All A., B. and C.

2. For most salts, the solubility increases with rise in temperature, but the solubility of _______________ is nearly independent of temperature rise?

   A. Sodium chloride
   B. Sodium carbonate monohydrate
   C. Anhydrous sodium sulphate
   D. Hypo

3. 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

4. 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.

5. The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of _____________ of water?

   A. Dissolved oxygen content
   B. Biological oxygen demand
   C. Vapor pressure
   D. All A., B. and C.

6. Thermal pollution due to excessive heat & temperature in the working place causes__________________?

   A. Reduction in working efficiency of manpower
   B. Fatigue
   C. High breathing rate
   D. All A., B. & C.

7. 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

8. 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

9. At a constant volume, for a fixed number of moles of a gas, the pressure of the gas increases with rise of temperature due to___________________?

   A. Decrease in mean free path
   B. Increased collision rate among molecules
   C. Increase in molecular attraction
   D. Increase in average molecular speed

10. Waste/polluted water discharged from electroplating, blast furnace and coal mining industries contain mainly _____________ substances?

    A. Radioactive
    B. Organic
    C. Inorganic
    D. None of these