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. Paraffinic
- B. Intermediate
- C. Naphthenic
- D. Mixed
Explanation: Naphthenic crude oils are relatively rich in asphaltic and resinous material, making them suitable for producing high-quality bitumen.
Correct answer: Naphthenic- A. 40-60
- B. 350-400
- C. 250-300
- D. 100-130
Explanation: Petrol is a relatively light hydrocarbon mixture, typically covering roughly C₅ to C₁₂ and having an average molecular weight near 100 to…
Correct answer: 100-130- A. 4
- B. 10
- C. 18
- D. 26
Explanation: Kerosene is a middle-distillate fraction, and its yield from straight-run crude distillation is commonly around 10 percent, though the…
Correct answer: 10- A. Pour point
- B. Volatility
- C. Viscosity index
- D. None of these
Explanation: A high viscosity index means the lubricant's viscosity changes only slightly with temperature, allowing it to work over a broad…
Correct answer: Viscosity index- A. Improve the octane number
- B. Increase its pour point
- C. Reduce its viscosity
- D. Act as an antioxidant
Explanation: Phenols act as antioxidants by interrupting free-radical oxidation reactions that produce gums and other unstable products in gasoline.
Correct answer: Act as an antioxidant- A. Higher yield of straight run gasoline
- B. Higher octane number gasoline
- C. Lower viscosity index lube oil
- D. Poorer yield of lube oil
Explanation: Paraffin-base crude generally contains a larger gasoline-forming fraction and therefore gives a higher yield of straight-run gasoline.
Correct answer: Higher yield of straight run gasoline- A. 1
- B. 50
- C. 5000
- D. 10000
Explanation: Ethyl mercaptan is added to LPG in a very small concentration, commonly around 50 ppm, because its intense odour makes leaks detectable…
Correct answer: 50- A. Low porosity
- B. High permeability
- C. Both B. and C.
- D. High porosity
Explanation: A useful petroleum reservoir rock needs high porosity to store oil and gas and high permeability to allow their flow toward the well.
Correct answer: Both B. and C.- A. Amyl nitrate
- B. Pyridine
- C. Mercaptans
- D. Alcohols
Explanation: Alcohols such as isopropyl alcohol absorb or disperse water and help prevent ice formation in fuel-system passages.
Correct answer: Alcohols- A. Produces i-octane from cracked gases containing i-butane and butene
- B. Causes olefins to combine with each other
- C. Causes aromatics to combine with each other
- D. Is aimed at producing lubricating oil
Explanation: Polymerisation joins olefin molecules together to form larger hydrocarbons, often improving the gasoline-range product yield.
Correct answer: Causes olefins to combine with each other- A. Decolorizes & stabilises cracked gasoline
- B. Desulphurise straight run gasoline & kerosene
- C. All A., B. & C.
- D. Adsorb arsenic from feedstock to catalytic reforming
Explanation: Clay treatment uses adsorption to remove colour bodies, gums and other impurities, so it can stabilize cracked gasoline, improve…
Correct answer: All A., B. & C.- A. Residual crude
- B. Petrolatum
- C. Reduced crude
- D. Residuum
Explanation: The heavy bottom product from a vacuum crude distillation unit is called vacuum residuum, commonly shortened to residuum.
Correct answer: Residuum- A. Crystallise out at low temperature
- B. Are not soluble in them
- C. Can be separated out by distillation
- D. Decrease their viscosity
Explanation: Petroleum waxes remain dissolved at sufficiently high temperature but crystallize as the product is cooled, causing cloudiness and…
Correct answer: Crystallise out at low temperature- A. Cloud point
- B. Freezing point
- C. Colour
- D. Pour point
Explanation: Jet fuel must remain fluid at the very low temperatures encountered during high-altitude flight, making freezing point the critical…
Correct answer: Freezing point- A. Increase the yield of light distillates
- B. Enhance the octane number of gasoline
- C. Suppress coke formation
- D. Reduce gum content in gasoline
Explanation: Although pressure slows thermal cracking, it is maintained to reduce the tendency of cracked vapours to form coke in the furnace and…
Correct answer: Suppress coke formation1676. Crude oil is transported inland from oil field to refineries, mainly by the _____________________?
- A. Road tankers
- B. Rail tankers
- C. None of these
- D. Underground pipelines
Explanation: Underground pipelines provide continuous, economical and safer transport of large crude-oil volumes from oil fields to refineries.
Correct answer: Underground pipelines- A. Pensky-Martens (closed cup type)
- B. Abel
- C. None of these
- D. Cleveland (open cup type)
Explanation: Atmospheric distillation residue is a relatively heavy product with a high flash point, so it is tested in the Cleveland open-cup…
Correct answer: Cleveland (open cup type)- A. 25
- B. 35
- C. 45
- D. 65
Explanation: Naval diesel fuel requires good ignition quality, commonly specified by a minimum cetane number of about 45.
Correct answer: 45- A. Lubricating oil > petrol > diesel > LPG
- B. Lubricating oil > diesel > petrol > LPG
- C. Petrol > lubricating oil > diesel > LPG
- D. Petrol > diesel > LPG > lubricating oil
Explanation: Higher-boiling petroleum fractions are heavier: lubricating oil boils above diesel, diesel above petrol, and LPG has the lowest boiling…
Correct answer: Lubricating oil > diesel > petrol > LPG- A. Fluid
- B. Flexi
- C. Delayed
- D. Contact
Explanation: Delayed coking is widely used in Indian refineries because it converts heavy residue into lighter products and solid petroleum coke…
Correct answer: Delayed