All Free Chemical Engineering MCQs with Answers
Every Chemical Engineering question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
6,983 questions · page 298 of 350
- A. 22
- B. 42
- C. 332
- D. 1050
Explanation: The historical water-supply limit listed for DDT in many chemical-engineering environmental tables is about 42 micrograms per litre.
Correct answer: 42- A. Electrostatic precipitator
- B. Scrubber
- C. Bag filter
- D. Cyclone separator
Explanation: Electrostatic precipitators are highly effective for collecting fine particulate matter because electrically charged particles migrate to…
Correct answer: Electrostatic precipitator- A. 25
- B. 50
- C. 70
- D. 85
Explanation: A quiet private office is typically around 50 decibels, whereas 70 dB is noticeably noisy and 85 dB approaches a level requiring…
Correct answer: 50- A. Radioactive rays
- B. Thermal pollution
- C. SPM
- D. Noise pollution
Explanation: Suspended particulate matter consists of physical particles and therefore has mass or weight.
Correct answer: SPM- A. Roentgen
- B. None of these
- C. Hertz
- D. Decibel
Explanation: Sound intensity or noise level is measured on the decibel (dB) scale. Hertz measures frequency, while roentgen measures ionising radiation…
Correct answer: Decibel- A. A combination of smoke and fog
- B. Nothing but black smoke
- C. A liquid particle resulting from vapor condensation
- D. A solid particle e.g. fly-ash
Explanation: The word smog combines smoke and fog, describing polluted air containing fine particles and droplets.
Correct answer: A combination of smoke and fog- A. 10-100
- B. < 1
- C. 100-200
- D. 100-1000
Explanation: Phosgene is extremely toxic, with a permissible exposure limit well below 1 ppm, commonly quoted near 0.1 ppm.
Correct answer: < 1- A. 10000
- B. 5
- C. 500
- D. 1000
Explanation: Aquatic organisms generally require dissolved oxygen of about 5 mg/L or more for healthy survival.
Correct answer: 5- A. CO
- B. SO2
- C. NOx
- D. CFC (chloro fluoro carbons)
Explanation: Carbon monoxide is not normally identified as a major direct ozone-depleting pollutant, unlike stratospheric chlorine from CFCs and some…
Correct answer: CO- A. Potable water
- B. Industrial effluents
- C. Distilled water
- D. Cooling water
Explanation: BOD measures the oxygen microorganisms require to biologically decompose organic matter in wastewater, so it is important for assessing…
Correct answer: Industrial effluents- A. 102
- B. 105
- C. 109
- D. 1015
Explanation: Ultraviolet radiation releases chlorine radicals from CFCs, and the radicals repeatedly catalyse ozone destruction.
Correct answer: 1055952. The average thickness of ozone layer in stratosphere is about _______________ dobson unit (DU)?
- A. 20
- B. 230
- C. 750
- D. 1500
Explanation: Atmospheric ozone is commonly reported in Dobson units, with a representative stratospheric value near 230 DU in many…
Correct answer: 230- A. Reheating furnace
- B. Soaking pit
- C. Open hearth furnace
- D. Cupola
Explanation: A reheating furnace commonly has separate preheating, heating and soaking zones.
Correct answer: Reheating furnace- A. Glass melting furnace
- B. All A., B. and C.
- C. By product coke ovens
- D. Open hearth furnace
Explanation: Regenerators recover heat from outgoing furnace gases and use it to preheat combustion air.
Correct answer: All A., B. and C.- A. Burning carbon monoxide and other incombustible in upper zone of furnace by supplying
- B. Supply of excess air
- C. Supply of excess fuel
- D. more air
- E. None of these
Explanation: Overfire burning occurs when carbon monoxide and other unburned combustibles burn in the upper furnace zone after additional air is…
Correct answer: Burning carbon monoxide and other incombustible in upper zone of furnace by supplying- A. Coke ovens
- B. Annealing furnace
- C. None of these
- D. Glass tank furnace
Explanation: A glass tank furnace operates continuously, with raw batch fed at one end and molten glass withdrawn at the other.
Correct answer: Glass tank furnace- A. Range of fuel firing rates
- B. Volume of the combustion chamber
- C. Maximum heat input rate only
- D. Minimum heat input rate only
Explanation: The turndown ratio is the ratio of a burner’s maximum to minimum stable firing rate.
Correct answer: Range of fuel firing rates5958. A refractory wall separating the stock and the source of heat is provided in a__________________?
- A. Updraft kiln
- B. Muffle furnace
- C. Continuous furnace
- D. None of these
Explanation: In a muffle furnace, a refractory muffle wall lies between the stock and the combustion gases or heat source.
Correct answer: Muffle furnace- A. Reheating furnace
- B. Reverberatory furnace
- C. Boiler furnace
- D. Rotary kilns
Explanation: A boiler furnace is thermally efficient because heat released by combustion is transferred directly to boiler water, while the…
Correct answer: Boiler furnace5960. Ingress of cold air in the furnaces through cracks, charging doors, openings etc ________________?
- A. Reduces the flue gas temperature and makes the furnace atmosphere oxidising
- B. Increases the load on the induced draft fan
- C. Reduces the furnace draught
- D. All A., B. and C.
Explanation: Leaking cold air dilutes and cools the flue gas, introduces excess oxygen that produces an oxidising atmosphere, and increases the gas…
Correct answer: All A., B. and C.