Free Chemical Process Principles MCQs with Answers
2,710 Chemical Process Principles MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. Bacterial stability factor
- B. Biological oxygen demand (BOD)
- C. Relative stability
- D. Oxygen ion concentration
Explanation: Relative stability compares the oxygen available in sewage with the oxygen required to stabilise its biodegradable matter.
Correct answer: Relative stability- A. t = 15 - 0.0035h
- B. t = 15 + 0.0065h
- C. t = 0.0035h -15
- D. t = 15 - 0.0065h
Explanation: The standard tropospheric environmental lapse rate is about 0.0065°C per metre, so temperature decreases from 15°C as height increases: t…
Correct answer: t = 15 - 0.0065h- A. H2S, NO & SO3
- B. CO, CO2 & SO2
- C. CO2, H2S & NO2
- D. SO3, NO2 & CO2
Explanation: Iron and steel production releases carbon oxides from fuel and carbon reactions, along with sulphur dioxide from sulphur-containing fuels…
Correct answer: CO, CO2 & SO2- A. Biological oxygen pond
- B. Lagoons
- C. Radial settling tank (thickener) using coagulant (lime & ferrous sulphate)
- D. Filtration
Explanation: Blast-furnace gas-cleaning water contains heavy suspended solids that are removed by coagulation followed by radial settling and…
Correct answer: Radial settling tank (thickener) using coagulant (lime & ferrous sulphate)- A. Bronchitis
- B. None of these
- C. Pneumoconiosis
- D. Silicosis
Explanation: Silicosis is the specific lung disease caused by prolonged inhalation of crystalline silica dust.
Correct answer: Silicosis226. Particles having diameter greater than 75 μm (micrometer = 10-6 mm) are called__________________?
- A. Grit
- B. Dust
- C. Powder
- D. Smoke
Explanation: In the usual industrial air-pollution classification, particles larger than about 75 micrometres are termed grit, while finer particles…
Correct answer: Grit- A. By chemical coagulation
- B. In vacuum filter
- C. In sedimentation tanks equipped with mechanical scrapper
- D. In clarifiers
Explanation: Wastewater containing about 3% clay, slate and stone is handled by gravity settling in tanks fitted with mechanical scrapers to remove the…
Correct answer: In sedimentation tanks equipped with mechanical scrapper- A. None of these
- B. Suspended solids
- C. Dissolved solids
- D. Dissolved gases
Explanation: Aeration brings water into contact with air and strips volatile dissolved gases such as carbon dioxide and hydrogen sulphide.
Correct answer: Dissolved gases- A. Activated carbon adsorption
- B. Lagooning
- C. Biological oxidation pond
- D. Chemical coagulation
Explanation: Activated carbon is highly effective for polishing water containing small concentrations of dissolved organic compounds because it adsorbs…
Correct answer: Activated carbon adsorption- A. Skimming off
- B. Sedimentation
- C. Chlorination
- D. Biological oxidation
Explanation: Sedimentation removes suspended solids by allowing the denser particles to settle under gravity, making it simple and economical for large…
Correct answer: Sedimentation- A. Ion exchange process
- B. Oxidation followed by settling & filtration
- C. Chlorination
- D. Lime soda process or manganese zeolite process
Explanation: Chlorination can oxidise iron and, to a limited extent, manganese, but it does not by itself remove the resulting precipitates from water…
Correct answer: Chlorination- A. Characterisation of solid wastes
- B. Organic concentration in gaseous effluents
- C. Characterisation of boiler feed water
- D. Characterisation of liquid effluents
Explanation: BOD measures the oxygen required by microorganisms to biologically oxidise biodegradable organic matter, so it is used to characterise…
Correct answer: Characterisation of liquid effluents- A. Gravity settling chamber
- B. Electrostatic precipitator
- C. Cyclone separator
- D. Bag filter
Explanation: An electrostatic precipitator gives very high collection efficiency for fine fly ash in large thermal-power-plant flue-gas flows, with…
Correct answer: Electrostatic precipitator- A. Low excess air
- B. Gaseous fuel in the furnace
- C. Very high excess air
- D. Liquid fuel in the furnace
Explanation: Very high excess air dilutes and cools the furnace gases, increasing the chance that water vapour condenses and appears as a white plume…
Correct answer: Very high excess air- A. 50 ppm
- B. 100 ppm
- C. 300 ppm
- D. 700 ppm
Explanation: Hydrogen sulfide becomes rapidly life-threatening at several hundred ppm, and around 700 ppm can cause collapse, respiratory failure, and…
Correct answer: 700 ppm- A. Ra-226
- B. Sr-90
- C. Au-198
- D. I-131
Explanation: Radium-226 undergoes a decay series that produces alpha and beta particles along with gamma radiation, unlike the other listed isotopes…
Correct answer: Ra-226- A. Foaming from boilers
- B. Its dissolved oxygen content
- C. Its silica content
- D. Caustic embrittlement
Explanation: Deaeration strips dissolved gases, especially oxygen, from boiler feed water.
Correct answer: Its dissolved oxygen content- A. Phosphate
- B. Brine
- C. Mercury
- D. None of these
Explanation: Mercury is associated with the mercury-cell chlor-alkali process and has also been used in battery manufacture, making it a common…
Correct answer: Mercury- A. Highly
- B. Very extremely
- C. Extremely
- D. Moderately
Explanation: A permissible concentration of 100 to 1000 ppm is conventionally classified as a moderately toxic gas range.
Correct answer: Moderately- A. Methyl isocyanate (MIC)
- B. Phosgene
- C. Carbon monoxide
- D. Sulphur dioxide
Explanation: The Bhopal disaster followed the release of methyl isocyanate, or MIC, from a pesticide plant in 1984.
Correct answer: Methyl isocyanate (MIC)