All Free Chemical Engineering MCQs with Answers

• 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…

• 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…

• 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.

• 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.

• 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…

• 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.

• 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.

• 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.

• 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…

• 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.

• 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…

• 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…

• 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…

• 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.

• 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…

• 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.

• 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…

• 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…

• A. 79
• B. 87
• C. 97
• D. > 100

Explanation: Aviation gasoline can have an octane rating above 100 because aviation fuels are often rated against performance numbers rather than being…

• A. Bomb method and lamp method
• B. Lamp method and bomb method
• C. Bomb method and quartz tube method
• D. Quartz tube method and lamp method

Explanation: The lamp method is commonly used for sulphur determination in lighter petroleum products, while heavier products are tested by the bomb…