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 297 of 350
- A. Kerosene
- B. Water
- C. Sodium stearate
- D. Lime water
Explanation: Sodium stearate forms a soap-like lubricating film that reduces friction between the die and the steel wire during drawing.
Correct answer: Sodium stearate- A. Venturi scrubber
- B. Packed column
- C. Bubble cap plate column
- D. Wetted wall column
Explanation: A venturi scrubber injects and atomizes liquid into a high-velocity gas stream, producing liquid dispersion as fine droplets.
Correct answer: Venturi scrubber- A. 100
- B. 0
- C. 50
- D. None of these
Explanation: At 100% relative humidity, the air is saturated and no evaporation occurs from the wet bulb, so wet-bulb and dry-bulb temperatures become…
Correct answer: 100- A. Dry bulb
- B. Dew point
- C. Wet bulb
- D. None of these
Explanation: A psychrometer directly measures dry-bulb and wet-bulb temperatures; the dew-point temperature is calculated from these readings and the…
Correct answer: Dew point5925. The dew point of moist air becomes ____________________ with decrease in its relative humidity ?
- A. More than the dry bulb temperature
- B. More than the wet bulb temperature
- C. Less than the wet bulb temperature
- D. Equal to wet bulb temperature
Explanation: At a fixed dry-bulb temperature, lowering relative humidity lowers the water-vapour partial pressure and hence the dew-point temperature.
Correct answer: Less than the wet bulb temperature- A. Specific humidity
- B. Dry bulb temperature
- C. Relative humidity
- D. Wet bulb temperature
Explanation: During adiabatic evaporative cooling, sensible heat is converted into latent heat, so the wet-bulb temperature remains approximately…
Correct answer: Wet bulb temperature- A. 0.15
- B. 1.5
- C. 4.5
- D. 6.5
Explanation: A typical domestic refrigerator has a small refrigeration capacity, commonly around 0.1 to 0.25 ton of refrigeration.
Correct answer: 0.15- A. Biological oxygen pond
- B. Aerated lagoons
- C. Gravity separator having oil skimming devices
- D. Trickling filters
Explanation: Free oil floats because its density is lower than water, so it can be separated by gravity in an oil-water separator fitted with skimming…
Correct answer: Gravity separator having oil skimming devices5929. Shouting by a man at his full voice corresponds to a voice level of about _____________ decibels?
- A. 25
- B. 50
- C. 80
- D. 120
Explanation: A person shouting at full voice produces approximately 80 dB of sound, far above ordinary conversation at about 60 dB.
Correct answer: 80- A. 1
- B. 3
- C. 7
- D. 20
Explanation: Carbon dioxide becomes acutely life-threatening at concentrations above roughly 20% by volume, causing severe oxygen displacement and…
Correct answer: 20- A. Methane
- B. All A., B. and C.
- C. Chlorofluoro carbons (CFC)
- D. Nitrous oxide
Explanation: Methane, nitrous oxide, and CFCs all absorb outgoing infrared radiation and therefore act as greenhouse gases.
Correct answer: All A., B. and C.- A. Remain constant
- B. Increases
- C. Decreases
- D. May increase or decrease; depends on the chemical characteristics of polluted water
Explanation: As water temperature rises, viscosity falls and particle collisions and floc formation generally improve, so less coagulant is usually…
Correct answer: Decreases- A. Global warming
- B. Ionosphere
- C. Atmospheric effect
- D. Green house
Explanation: A greenhouse allows incoming short-wave solar radiation to pass while restricting the escape of long-wave infrared radiation, causing heat…
Correct answer: Green house- A. Cancer
- B. Silicosis
- C. Respiratory disease (e.g., asthma)
- D. Reduced crop yield
Explanation: Carcinogenic hydrocarbons can damage cellular DNA and initiate uncontrolled cell growth, leading to cancer.
Correct answer: Cancer- A. Smog & ozone
- B. Hydrogen fluoride & nitrogen oxides
- C. Carbon monoxide
- D. Sulphur dioxide & spray of weed killers
Explanation: Carbon monoxide is highly toxic to humans because it binds haemoglobin, but it is generally not considered a major direct cause of…
Correct answer: Carbon monoxide- A. 100
- B. 1000
- C. 400
- D. 4000
Explanation: A 1,000-metre exclusion radius is the commonly cited planning buffer for hazardous or highly polluting chemical industries, with a green…
Correct answer: 1000- A. 20
- B. 60
- C. 90
- D. 120
Explanation: The commonly used maximum exposure limit for continuous occupational noise over an 8-hour shift is about 90 dBA.
Correct answer: 90- A. Coagulation
- B. Disinfection
- C. Sterilisation
- D. Sedimentation
Explanation: Disinfection destroys or inactivates disease-causing microorganisms in water, commonly using chlorine, ozone, or ultraviolet light.
Correct answer: Disinfection- A. Acidic
- B. Alkaline
- C. Neutral
- D. Highly acidic
Explanation: Fresh domestic sewage is commonly slightly alkaline, typically having a pH near 7 to 8.
Correct answer: Alkaline- A. 5
- B. 50
- C. 500
- D. 5000
Explanation: A commonly cited permissible or threshold concentration for sulphur dioxide in air is about 5 ppm, although modern ambient-air standards…
Correct answer: 5