chemical engineering chemical environmental engineering chemical engineering Mcqs
1. Infective bacteria in water is killed by the _____________ process?
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A. Sterilisation

B. Aeration

C. Disinfection

D. None of these

2. Pick out the wrong statement ?
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A. The concentric layer in atmosphere which contains about 70% of the total mass of atmosphere

B. Troposphere is a turbulent dusty zone containing much of water vapor and clouds

C. The earths atmosphere is an envelope of gases extending upto a height of about 200 kms

D. Stratosphere is rich in ozone and is located just above the troposphere

E. characterised by a steady decrease in temperature is called stratosphere</strong>

3. Corrosion in boilers can be prevented by _________________?
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A. Feeding sodium sulphite or hydrazine phosphate to the boilers, which combines with oxygen

B. All A., B. and C.

C. Deaeration of feed water

D. prevents corrosion

E. Enhancing pH of feed water by adding alkali

4. TLV of NO2 & NO exposure for the human being is 5 & 25 ppm respectively. Prolonged exposure of human being to NO2 causes_________________?
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A. Skin disorder

B. Bronchitis

C. Cancer

D. Bone disease

5. In a sedimentation tank, the detention period for water ranges from _____________ hours?
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A. 2 to 4

B. 24 to 32

C. 8 to 12

D. 16 to 20

6. Fresh domestic sewage is _______________ in color?
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A. Grey

B. Black

C. Red

D. Dark brown

7. Exposure to chemicals having carcinogenic properties cause ____________________?
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A. Cancer

B. Asphyxiation (suffocation)

C. Asthma

D. Dermatitis (skin disorder)

8. The weakest sound that can be heard by a person in a quiet environment is equivalent to ____________ decibel ?
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A. 50

B. 10

C. 5

D. 1
9. The common pollutant generated in chlor-alkali industry and battery manufacture is ___________________?
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A. Phosphate

B. None of these

C. Brine

D. Mercury
10. On prolonged exposure to high concentration of carbon monoxide (> 5000 ppm), man dies because __________________?
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A. Of jamming of respiratory tract

B. It forms carboxyhemoglobin by combining with haemoglobin of blood, thereby making it

C. apable of absorbing oxygen</strong>

D. It forms CO2 by combining with oxygen present in the blood

E. Of clotting of blood

11. Aerosols present in atmospheric air may be__________________?
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A. Neutral

B. Positively charged

C. Combination of all A., B. & C.

D. Negatively charged

12. Which of the following gases is having the widest explosion limit (about 2 to 81% gas in gasair mixture), rendering it the property of the most explosive gas ?
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A. Hydrogen

B. Acetylene

C. Carbon monoxide

D. Ammonia

13. Threshold limit value (TLV) means maximum permissible/acceptable concentration. TLV of phosgene in air is about ______________ ppm (parts per million)?
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A. 0.002

B. 4.8

C. 1.2

D. 0.2
14. Exposure to chemicals having carcinogenic properties cause___________________?
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A. Asphyxiation

B. Dermatitis (skin disorder)

C. Cancer

D. Asthma

15. Which of the following is the most lethal water pollutant ?
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A. Phenol and cyanide

B. Alkalis

C. Suspended solids

D. Chlorine

16. Which of the following air pollutants is not toxic to vegetation i.e., doesnt cause vegetation damage ?
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A. Hydrogen fluoride & nitrogen oxides

B. Sulphur dioxide & spray of weed killers

C. Smog & ozone

D. Carbon monoxide
17. Bacterial aerobic oxidation of polluted water in biological oxidation ponds is done to purify it. Presence of bacteria helps in____________________?
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A. Nitrification or oxidation of ammonia derived from breakdown of nitrogenous organic matter

B. Coagulation and flocculation of colloids

C. All A., B. and C.

D. Oxidation of carbonaceous matter to CO2

E. the nitrite and eventually to the nitrate

18. In water treatment plant, zeolite process is used to remove the _____________ of water?
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A. Acidity

B. Iron & zinc

C. Hardness

D. Alkalinity

19. Noise level inside a jet airliner in normal flight is about ______________ decibels?
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A. 80

B. 125

C. 150

D. 100
20. The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of _____________ of water?
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A. All A., B. and C.

B. Vapor pressure

C. Biological oxygen demand

D. Dissolved oxygen content
21. Peroxyacetyl nitrate (PAN), a pollutant is found in the_________________?
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A. Flue gas of coal based power plant

B. Exhaust of nitric acid plant

C. Exhaust of sulphuric acid plant

D. Automobile exhaust
22. _____________ plant emits large amount of SO2 as an air pollutant?
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A. Chlor alkali

B. Sulphuric acid

C. Iron & steel

D. Nitric acid

23. Out of the following, TLV of _______________ is maximum (about 500 ppm)?
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A. Toluene

B. Acetaldehyde

C. Carbon disulphide

D. Carbon dioxide
24. Radioactive solid nuclear wastes are disposed off by _________________?
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A. Pathological incineration

B. High temperature incineration

C. Underground burial in concrete containers

D. Pyrolysis

25. Black smoke coming out of the chimney of a furnace is an indication of the use of ______________ in the furnace?
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A. Pulverised coal as fuel

B. Large quantity of excess combustion air

C. Low amount of excess combustion air

D. Hydrocarbon fuel

26. Which of the following is not a natural source of air pollution ?
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A. Biological decay of vegetable matter

B. Volcanic eruptions and lightening discharges

C. Photochemical oxidation of organic matter

D. None of these
27. Beyond what concentration of H2S in air, acute danger to human life exists ?
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A. 100 ppm

B. 700 ppm

C. 300 ppm

D. 50 ppm

28. The destruction of water-borne pathogens is termed as disinfection of water. Which of the following is a water disinfectant ?
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A. Chlorine

B. Alkyl benzene sulphonate (ABS)

C. Alkalis

D. Benzene hexachloride

29. The main type of sludge gas evolved during sewage treatment in Imhoff tank is___________________?
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A. CH4

B. H2

C. CO

D. CO2

30. Which of the following industries discharge mercury as a pollutant ?
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A. Beverage plant

B. Tanneries

C. Phosphoric acid plant

D. Chloro-alkali industry
31. A shallow pond in which the sewage is retained and biologically treated is called__________________?
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A. Oxidation

B. Lagoon

C. Skimming tank

D. Imhoff tank

32. Which of the following fine dust removal equipments is the most efficient ?
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A. Electrostatic precipitator

B. Scrubber

C. Bag filter

D. Cyclone separator

33. The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the __________________?
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A. Bacterial stability factor

B. Oxygen ion concentration

C. Biological oxygen demand (BOD)

D. Relative stability
34. CFC (chloro fluoro carbon) is very highly reactive in causing depletion of ozone layer in the atmosphere. Each atom of chlorine liberated from CFC is capable of decomposing ________________ molecules of ozone?
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A. 105

B. 1015

C. 102

D. 109

35. Automobile exhaust is passed through two compartments catalytic converter employing platinum as catalyst for___________________?
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A. Oxidation of unburnt hydrocarbon fuel in the second compartment

B. Conversion of CO into CO2 in the second compartment

C. Conversion of NOx into N2 and NH3 in the first compartment

D. All A., B. and C.
36. A man exposed to excessive noise level in the working environment may suffer from____________________?
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A. Nervousness & fatigue

B. Hearing loss

C. Rupture of ear drum

D. All A., B. & C.
37. Threshold limit value (TLV) i.e., the maximum permissible safe limit of phosgene gas which Hitler used to use to kill his enemies in gas chamber is about ______________ ppm?
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A. 100-200

B. 100-1000

C. < 1

D. 10-100

38. Maximum allowable noise exposure limits for a man working for 8 hours a day in a noisy chemical plant is about ______________ decibels?
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A. 120

B. 20

C. 90

D. 60

39. Presence of nitrogen and phosphorous in waste water discharged into lakes and ponds causes_______________?
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A. Odour nuisances

B. Undesirable plant growth

C. Turbidity

D. Foaming

40. Maximum permissible limit of industrial noise as recommended by World Health Organisation (WHO) is _____________ decibels?
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A. 35

B. 105

C. 95

D. 75
41. A masonry structure built below ground level, where biochemical reaction takes place due to anaerobic bacteria is called___________________?
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A. Lagoon

B. Skimming mill

C. Cesspool

D. Septic tank
42. Which of the following is the most widely used disinfectant in water treatment ?
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A. Chlorine

B. Coagulation

C. Cation exchanger

D. Irradiation of water by ultraviolet light

43. Presence of carbon monoxide in atmosphere produced by decomposition of chlorophyll and haemoglobin breakdown of some animals, beyond TLV (>50 ppm) ?
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A. Acts as a green house gas thereby raising earths temperature

B. Enhances the green house effect

C. Causes increase in sea level

D. Causes asphyxia
44. Which of the following is the most efficient for removal of very finely divided suspended solids and colloidal matter from the polluted water stream ?
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A. Chemical coagulation

B. Mechanical flocculation

C. Sedimentation tank

D. Circular clarifier

45. Methyl isocyanate (MIC) gas (TLV <1 ppm), which caused Bhopal gas tragedy in 1984 falls under the category of ______________ toxic gas?
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A. Extremely

B. Moderately

C. Very extremely

D. Highly

46. The function of skimming tank in sewage treatment is to remove _____________ substances?
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A. Gritty & inorganic

B. Suspended solid

C. Dissolved solid

D. Oil & fatty
47. Which is the most efficient dust removal equipment for removal of submicronic dust particles from blast furnace gas ?
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A. Electrostatic precipitator

B. Hydrocyclone

C. Packed scrubber

D. Gravity settling chamber

48. The biological decomposition of organic substances in wastes controlled conditions is called_________________?
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A. Composting

B. Incineration

C. Biological oxidation

D. None of these

49. Exposure to SO2 containing chimney gases results in the__________________?
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A. All A., B. and C.

B. Reduction in strength of leather & cloth

C. Acceleration of corrosion rates of metals

D. Increased drying & hardening time of paints

50. Presence of _____________ bacteria in water causes disease like typhoid?
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A. Anaerobic

B. Aerobic

C. Pathogenic

D. Non-pathogenic