chemical engineering MCQs – Page 397

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
7921. Thermal pollution of water increases its toxicity and oxidation of oxygen demanding waste besides favouring bacterial growth. A rise in water temperature by 10C, doubles the toxic effects of _____________ present in it?
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A. Coal ash

B. None of these

C. Potassium cyanide

D. Ortho-xylene

7922. Out of the following, TLV of _______________ is maximum (about 500 ppm)?
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A. Acetaldehyde

B. Carbon dioxide

C. Carbon disulphide

D. Toluene

7923. 5-200 ?m size particles are called__________________?
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A. Dust

B. Colloids or aerosols

C. Powder

D. Smoke

7924. Noise emitted by a ventilation fan at a distance of 3 metres is about _____________ decibels?
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A. 125

B. 85

C. 105

D. 145

7925. Pick out the wrong statement?
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A. orosis

B. Loamy soil is the best soil for vigorous plant growth, while the clayey soil is solid and hence

C. Large excess use of nitrogenous fertiliser in land causes the problem of diarrhoea and cyanosis

D. plant roots penetrate with difficulty

E. Cereal crops grown on alkaline soil absorb higher amount of fluorides thereby spreading

F. Application of large excess of Potassic fertiliser in soil increases the valuable carotene in
7926. Which of the following causes death by asphyxiation, if its presence in atmospheric air exceeds maximum allowable concentration (i.e. > 50 ppm) ?
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A. Carbon monoxide

B. Sulphur dioxide

C. Benzopyrene

D. Peroxyacetyl nitrate

7927. The most commonly used chemical coagulant in water treatment is________________?
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A. Lime

B. Hydrazine

C. Ferrous sulphate

D. Alum
7928. Main pollutants released from iron & steel industry is__________________?
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A. CO, CO2 & SO2

B. SO3, NO2 & CO2

C. CO2, H2S & NO2

D. H2S, NO & SO3

7929. Sooty and sulphurous smog formed due to combustion of fossil fuels particularly in winter, continues throughout the day and night. When the moist atmospheric airs water vapor condenses on the solid particles of smoke thereby forming smog (smoke + fog), it causes_________________?
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A. Poor visibility due to sky darkening

B. All A., B. and C.

C. Respiratory trouble

D. Irritation in eyes

7930. Which of the following plants does not emit appreciable amount of SO2 in atmosphere ?
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A. Nitric acid plant

B. Thermal power plant

C. Petroleum refinery

D. Sulphuric acid plant

7931. Aerodynamic noise resulting from turbulent gas flow is the most prevalent source of valve noise in fluid flow control. It is caused due to_________________?
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A. Reynold stresses

B. Shear forces

C. Both A. & B.

D. Neither A. nor B.

7932. When a gas is subjected to adiabatic expansion, it gets cooled due to__________________?
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A. Decrease in temperature

B. Decrease in kinetic energy

C. Energy spent in doing work

D. Decrease in velocity

7933. BOD of raw municipal sewage may be in the range of about _____________ mg/litre?
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A. 10-May

B. 2-Jan

C. 150-300

D. 2000-3000

7934. Maximum permissible turbidity in potable water is _____________ ppm?
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A. 1

B. 250

C. 10

D. 1000

7935. Septic tanks are used for the ______________ of the deposited solids?
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A. Separation

B. Anaerobic decomposition

C. Aerobic decomposition

D. None of these

7936. Atmospheric pollution caused by the exhaust gas of supersonic transport air-crafts is mostly in the atmospheric region called________________?
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A. Troposphere

B. Thermosphere

C. Stratosphere

D. Mesosphere

7937. Foaming and priming in boiler operation can be reduced by reduction in ______________ in feed water?
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A. Total solids

B. Color (Hazen)

C. All A., B. & C.

D. Turbidity

7938. Phenolic water generated in coke ovens & by-product plant attached to an integrated steel plant containing phenol in concentration of less than 100 mg/litre can be removed by_______________?
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A. None of these

B. Chlorination

C. Chemical coagulation

D. Treating in biological oxygen pond
7939. 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. Circular clarifier

B. Chemical coagulation

C. Mechanical flocculation

D. Sedimentation tank

7940. Worlds worst radioactive pollution was caused by nuclear reactor disaster which occured in ___________________?
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A. Arizona (U.S.A.)

B. Moscow (U.S.S.R.)

C. Chernobyl (undivided U.S.S.R.)

D. Pennsylvania (U.S.A.)