All Free Chemical Engineering MCQs with Answers
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6,983 questions · page 111 of 350
2201. In case of liquid petrofuels, momentary combustion is observed at its ________________________?
- A. Preheating temperature corresponding to viscosity of 25 centistokes
- B. Flash point
- C. Flame temperature
- D. Fire point
Explanation: At the flash point, vapours above the liquid ignite momentarily when exposed to a flame.
Correct answer: Flash point2202. ____________ is not an important refinery process for upgrading the quality of lubricating oil ?
- A. Hydro-treatment
- B. Solvent refining
- C. Clay treatment
- D. Deoiling
Explanation: Deoiling is mainly associated with separating oil from wax during wax processing, rather than upgrading the quality of the lubricating-oil…
Correct answer: Deoiling- A. Is optically active
- B. Constitutes mainly of olefins
- C. Does not contain asphalt
- D. Does not contain aromatics
Explanation: Petroleum can be optically active because some of its complex hydrocarbon molecules are chiral.
Correct answer: Is optically active- A. Diesel
- B. Fuel oil
- C. Kerosene
- D. Petrol
Explanation: Fuel oil is generally the heaviest of these products and retains more sulphur-containing compounds from the crude oil.
Correct answer: Fuel oil- A. Octane number
- B. Lead susceptibility
- C. Gum forming tendency & thoroughness of refining
- D. None of these
Explanation: Gasoline colour mainly reflects the presence of impurities, gum-forming materials, and how thoroughly the product was refined.
Correct answer: Gum forming tendency & thoroughness of refining- A. Catalytic cracking
- B. Alkylation
- C. Hydrotreating
- D. Catalytic reforming
Explanation: Catalytic reforming rearranges and dehydrogenates low-octane hydrocarbons to form aromatic compounds and isoparaffins, increasing gasoline…
Correct answer: Catalytic reforming- A. Olefins
- B. Paraffins
- C. Naphthenes
- D. None of these
Explanation: Isomerisation changes straight-chain paraffins into branched-chain isoparaffins, improving octane quality.
Correct answer: Paraffins- A. 2
- B. 6
- C. 12
- D. 18
Explanation: Straight-run distillation separates only the naturally occurring fractions of crude oil, and naphtha may constitute roughly 6% in the…
Correct answer: 6- A. Phenol
- B. Sodium plumbite
- C. Methanol
- D. Potassium isobutyrate
Explanation: Potassium isobutyrate acts as a solutizer, helping sulfur compounds remain accessible in the caustic phase during sweetening.
Correct answer: Potassium isobutyrate- A. 4
- B. 3
- C. 2
- D. 1
Explanation: The Reid vapor-pressure bomb uses an air chamber four times the volume of the liquid chamber, giving an air-to-liquid volume ratio of 4:1.
Correct answer: 4- A. Aniline point
- B. Flash point and acid value
- C. Dielectric strength
- D. Copper strip corrosion test
Explanation: Transformer oil is routinely checked for dielectric strength, acidity, flash point and corrosiveness; aniline point is mainly important…
Correct answer: Aniline point- A. Same as petroleum ether
- B. A mixture of microcrystalline wax in viscous hydrocarbon liquids
- C. Petroleum coke
- D. None of these
Explanation: Petrolatum, or petroleum jelly, is a semisolid blend of microcrystalline wax with viscous hydrocarbon oil.
Correct answer: A mixture of microcrystalline wax in viscous hydrocarbon liquids- A. Petroleum ether
- B. Naphtha
- C. Methyl-ethyl-ketone (MEK)
- D. Sodium plumbite
Explanation: MEK is widely used for solvent dewaxing, commonly in combination with toluene to maintain oil solubility while wax precipitates on…
Correct answer: Methyl-ethyl-ketone (MEK)- A. Thiophenes
- B. Pyrroles
- C. Sulphones
- D. Mercaptans
Explanation: Thiophenes, mercaptans and sulphones are recognised sulphur-containing petroleum compounds.
Correct answer: Pyrroles- A. One fourth
- B. One third
- C. Half
- D. One eighth
Explanation: Liquid LPG, mainly propane and butane, has a density of roughly 0.5 g/cc, about half the density of water.
Correct answer: Half- A. Paraffinic
- B. Aromatic
- C. Mixed
- D. Naphthenic
Explanation: Naphthenic-base crude contains substantial cycloparaffinic material and yields asphaltic residues, so it is commonly called asphaltic…
Correct answer: Naphthenic- A. Naphtha
- B. Kerosene
- C. LSHS
- D. Furnace oil
Explanation: Naphtha is a light petroleum fraction and generally contains less sulphur than heavier products such as kerosene, LSHS and furnace oil.
Correct answer: Naphtha- A. Nitrogen
- B. Sulphur
- C. Oxygen
- D. None of these
Explanation: Ethyl mercaptan, or ethanethiol, has the formula C₂H₅SH, so its characteristic functional group contains sulphur.
Correct answer: Sulphur- A. Obviate catalyst poisoning
- B. Maintain the reaction temperature
- C. Sustain the reactor pressure
- D. Hydrogenate the feed stock
Explanation: Hydrogen recycle maintains a high hydrogen partial pressure in the reformer, commonly described as sustaining reactor pressure and helping…
Correct answer: Sustain the reactor pressure- A. Oleophobic
- B. Oleophilic
- C. Both A. and B.
- D. Neither A. nor B.
Explanation: Electrical desalting removes water-soluble salts and other water-associated impurities from crude oil.
Correct answer: Oleophobic