Telegram group: T.me/BBCNOUN
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EMT411
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1. _______  affect the toxicity of many substances in the water.

	      alkalinity

	      pH

	      hardness

	--->> all of the above

2. Whenever the pH touches 8.3, the presence of ________ is indicated

	      dissolved oxygen

	      acid

	--->> carbonates

	      alkaline

3. Barium chloride is used for producing ________ due to barium sulphate and a mixture of organic substance (Glycerol or Gum acetia)

	--->> turbidity

	      carbonate

	      sulphate

	      sulphide

4. Biochemical Oxygen Demand is a measure of organic material contamination in _____ specified in mg/L.

	--->> water

	      soil

	      air

	      atmosphere

5. ________ is measured by nephelometric method in which the concentration of turbidity is measured against the known concentration of synthetically prepared sulphate solution.

	--->> sulphate

	      sulphide

	      carbonates

	      alkaline

6. Sodium chloride is used to prevent the settling of ______

	--->> turbidity

	      carbonate

	      sulphate

	      sulphide

7. ______ demands are key indicators of the environmental health of a surface water supply.

	      biochemical oxygen

	      chemical oxygen

	      carbon

	--->> A and B

8. ________ is measured spectroscopically at 425 nm radiation by making a colour complex with Nessler’s reagent

	      sulphate

	      Carbonate

	--->> Ammonia

	      turbidity

9. Chemical Oxygen Demand is the amount of dissolved _____ required to cause chemical oxidation of the organic material in water.

	      chemical

	--->> oxygen

	      water

	      none of the above

10. ________ in sample is measured titrimetrically by Winkler’s method after 5 days incubation at 293 K.

	      pH

	      alkalinity

	--->> total disolved solids

	      specific conductance