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. 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…
Correct answer: > 100- 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…
Correct answer: Bomb method and lamp method- A. Aromatic
- B. Naphthene
- C. Di-olefin
- D. Olefin
Explanation: Butadiene contains two carbon-carbon double bonds, so it is classified as a diolefin.
Correct answer: Di-olefin1684. The main use of heavy gas oil produced by the vacuum distillation unit is as a_____________________?
- A. Blending component for kerosene
- B. Blending component for petrol
- C. None of these
- D. Feedstock for fluid catalytic cracking unit
Explanation: Heavy gas oil from vacuum distillation has a high boiling range and is unsuitable for direct blending into petrol or kerosene.
Correct answer: Feedstock for fluid catalytic cracking unit- A. Anti-icing
- B. Anti-knocking
- C. Anti-gum forming
- D. Dewaxing
Explanation: Glycol lowers the freezing point of water and absorbs or ties up moisture, preventing ice formation in the fuel system or carburettor.
Correct answer: Anti-icing1686. Maximum sulphur percentage in low sulphur heavy stock (LSHS) furnace oil is about_________________?
- A. 0.1
- B. 1
- C. 2.5
- D. 3.5
Explanation: Low-sulphur heavy stock furnace oil is generally specified at about 1% sulphur.
Correct answer: 1- A. Impart colour to it, for easy identification
- B. Prevent icing of the carburettor
- C. Minimise the gum formation
- D. Prevent the lead build up in engines
Explanation: Antioxidants slow oxidation reactions in petrol, thereby reducing the formation of gums during storage.
Correct answer: Minimise the gum formation- A. Smoking tendency of hydrocarbons increases in the order: paraffins → isoparaffins →
- B. naphthenes → aromatics
- C. Smoking tendency of naphthenes decreases with its increasing molecular weight & also on
- D. Smoking tendency of paraffins increases with decrease in its molecular weight
- E. addition of double bond
- F. Smoking tendency of aromatics decreases with increase in its molecular weight
Explanation: The wrong statement is that paraffin smoking tendency increases as molecular weight decreases; it generally increases with increasing…
Correct answer: Smoking tendency of paraffins increases with decrease in its molecular weight- A. R-S-H
- B. R-COOH
- C. R-S-R
- D. R-S-R'
Explanation: Mercaptans are thiols, formed when a hydrogen atom is attached to sulfur in an organic group, so their general formula is R–SH.
Correct answer: R-S-H- A. 50
- B. 100
- C. 0
- D. ∞
Explanation: Alpha-methylnaphthalene is assigned a cetane number of 0 and serves as the low-cetane reference fuel.
Correct answer: 0- A. Sulphur
- B. Nitrogen
- C. None of these
- D. Oxygen
Explanation: Naphthenic acids are cycloalkane-based carboxylic acids, so they contain oxygen in the carboxyl group.
Correct answer: Oxygen- A. Gas heavier than air
- B. Liquid heavier than water
- C. Gas lighter than air
- D. Liquid lighter than water
Explanation: At atmospheric pressure and temperature, LPG vaporizes because its boiling points are below room temperature.
Correct answer: Gas heavier than air- A. 20-25
- B. 0-5
- C. 60-75
- D. 100-120
Explanation: A good-burning kerosene commonly has a smoke point around 20–25 mm. A higher smoke point indicates cleaner burning with less soot, while…
Correct answer: 20-25- A. Diesel
- B. Furnace oil
- C. Petrol
- D. Kerosene
Explanation: Furnace oil contains much heavier, less volatile hydrocarbons than diesel, kerosene, or petrol, so it requires the highest temperature to…
Correct answer: Furnace oil- A. 50
- B. 70
- C. 90
- D. 140
Explanation: Medium-viscosity furnace oil is commonly preheated to about 90°C so its viscosity falls enough for proper atomisation through the burner.
Correct answer: 90- A. Cyclohexane
- B. Butadiene
- C. Butene
- D. Acetylene
Explanation: Naphthenes are saturated cyclic hydrocarbons, and cyclohexane is a six-membered saturated ring.
Correct answer: Cyclohexane- A. Low pressure & temperature
- B. High pressure & temperature
- C. High pressure and low temperature
- D. High temperature and low pressure
Explanation: Hydrocracking combines catalytic cracking with hydrogenation, so it requires elevated temperature and especially high hydrogen pressure.
Correct answer: High pressure & temperature- A. Cracking
- B. Polymerisation
- C. Reforming
- D. Isomerisation
Explanation: Catalytic reforming converts straight-run naphtha into higher-octane gasoline by forming aromatics and branched hydrocarbons, with…
Correct answer: Reforming- A. Steam reforming
- B. None of these
- C. Desulphurisation
- D. Distillation
Explanation: Solvent naphtha is obtained by fractionating virgin naphtha into selected boiling-range cuts, which is a distillation operation.
Correct answer: Distillation- A. Both A. & B.
- B. Aromatics content
- C. Molecular weight
- D. Neither 'a' nor 'b'
Explanation: Refractive index varies with both the molecular characteristics of the fuel, including molecular weight, and its aromatic content.
Correct answer: Both A. & B.