Presence of a certain minimum quantity of fluorine is desirable in potable water to prevent___________________?

Related Mcqs:

1. Presence of excess fluorine in water causes__________________?

   A. Dental cavity
   B. Tooth decay
   C. Fluorosis
   D. Respiratory disease

2. Presence of bacteria in potable (drinking) water causes_________________?

   A. Turbidity
   B. Disease
   C. Bad odour
   D. Bad taste & colour

3. The pH value of potable water should be between____________________?

   A. 1 to 1.5
   B. 6.5 to 8
   C. 13 to 14
   D. 4 to 5

4. TLV of mercury in potable (drinking) water is about ______________ ppm?

   A. 0.001
   B. 0.1
   C. 1
   D. 5

5. Maximum permissible turbidity in potable water is _____________ ppm?

   A. 1
   B. 10
   C. 250
   D. 1000

6. Presence of soluble organics in polluted water causes_________________?

   A. Undesirable plants growth
   B. Depletion of oxygen
   C. Fire hazards
   D. Explosion hazards

7. Presence of iron and manganese in water causes___________________?

   A. Reduction in its dissolved oxygen content
   B. Discoloration of bathroom fixtures
   C. Temporary hardness
   D. None of these

8. Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes_______________?

   A. Foaming
   B. Odour nuisances
   C. Undesirable plant growth
   D. Turbidity

9. Presence of _____________ hardness is responsible for the temporary hardness in water?

   A. Carbonate
   B. Calcium
   C. Chloride
   D. Sulphate

10. Presence of ____________ in water stream are deleterious to aquatic life?

    A. Soluble and toxic organics
    B. Suspended solids
    C. Heavy metals and cyanides
    D. All A., B. & C.