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 131 of 350
- A. 80
- B. 90
- C. 98
- D. 100
Explanation: A four-pass sulphur dioxide converter achieves approximately 98% overall conversion to sulphur trioxide.
Correct answer: 98- A. Dehydration
- B. Oxidation
- C. Alkylation
- D. Dehydrogenation
Explanation: Styrene is formed from ethylbenzene by removing hydrogen from the side chain, producing a carbon-carbon double bond.
Correct answer: Dehydrogenation- A. Plaster of Paris
- B. Salt cake
- C. Nitre cake
- D. Lime
Explanation: Controlled heating of gypsum, calcium sulfate dihydrate, removes part of its water of crystallisation and forms calcium sulfate…
Correct answer: Plaster of Paris- A. 20% oleum
- B. 98% H2SO4
- C. 78% H2SO4
- D. 65% oleum
Explanation: About 98% sulfuric acid gives the best SO3 absorption because it has low water content without the excessive free SO3 present in oleum.
Correct answer: 98% H2SO42605. DDT should not be allowed to come in contact with iron (during its manufacture) to _______________?
- A. Avoid its decomposition
- B. Prevent sulphonation of the monochlorobenzene by the acid catalyst
- C. Achieve non-hygroscopic property
- D. None of these
Explanation: Iron must be excluded because it promotes decomposition of DDT during manufacture, reducing product quality.
Correct answer: Avoid its decomposition- A. Plasticisers
- B. Film forming materials
- C. Diluents
- D. Solvents
Explanation: Plasticisers are added to lacquer films to increase flexibility, thereby reducing brittleness and improving adhesion.
Correct answer: Plasticisers- A. SO2
- B. SO3
- C. H2SO3
- D. H2SO4
Explanation: The percentage in oleum denotes free sulfur trioxide dissolved in sulfuric acid, so 10% oleum contains 10% free SO3 by mass.
Correct answer: SO3- A. Platinum
- B. Silica gel
- C. Alumina
- D. Nickel
Explanation: In the Claus process, alumina is a common catalyst for converting hydrogen sulfide and sulfur dioxide into elemental sulfur.
Correct answer: Alumina- A. Alumina
- B. Platinum
- C. Iron
- D. Nickel
Explanation: Finely divided nickel is the conventional catalyst for hydrogenating vegetable oils, converting unsaturated bonds into more saturated…
Correct answer: Nickel- A. Decrease the cement setting rate
- B. Increase the density of cement
- C. Both A. and B.
- D. Neither A. nor B.
Explanation: Gypsum reacts with the aluminate phases in cement and slows their rapid hydration, giving cement workable setting time.
Correct answer: Decrease the cement setting rate- A. As a rocket fuel
- B. In water treatment
- C. As a disinfectant
- D. As fire retardant
Explanation: Hydrazine is a high-energy, readily decomposed fuel used in rockets and spacecraft propulsion systems.
Correct answer: As a rocket fuel- A. Phenol
- B. Naphthalene
- C. Styrene
- D. Benzoic acid
Explanation: Removing hydrogen from ethylbenzene forms a double bond in the side chain, producing vinylbenzene, commonly called styrene.
Correct answer: Styrene- A. Alum
- B. Washing soda
- C. Calcium carbide
- D. Soda ash
Explanation: The Leblanc process historically produced sodium carbonate, known commercially as soda ash.
Correct answer: Soda ash- A. Starch
- B. Maltose
- C. Sucrose
- D. Glucose
Explanation: Starch is a polysaccharide made of many glucose units joined in long chains.
Correct answer: Starch- A. Explosive
- B. Detergent
- C. Soap
- D. Analgesic drug
Explanation: Sodium dodecylbenzene sulfonate has a hydrophobic hydrocarbon tail and a hydrophilic sulfonate group, so it acts as a synthetic detergent.
Correct answer: Detergent- A. Flint
- B. Soda
- C. Pyrex
- D. Potash
Explanation: Pyrex is borosilicate glass, whose low thermal expansion reduces cracking during temperature changes and whose composition gives good…
Correct answer: Pyrex- A. Calcite
- B. Slaked lime
- C. Limestone
- D. Quick lime
Explanation: CaO is quicklime, also called burnt lime, and it is produced by heating limestone.
Correct answer: Quick lime- A. Liquefaction of permanent gases
- B. Storage & shipment of frozen foods and ice-creams
- C. Liquefaction of natural gas
- D. None of these
Explanation: Solid carbon dioxide sublimates at about −78.5°C, making dry ice useful for storing and shipping frozen foods and ice cream.
Correct answer: Storage & shipment of frozen foods and ice-creams- A. Bauxite
- B. Quartz
- C. Limestone
- D. Manganese
Explanation: Limestone acts as the flux in a blast furnace. It decomposes to lime, which combines with silica and other earthy impurities to form a…
Correct answer: Limestone- A. Usually soft soap (made from coconut oil) in which cane sugar & alcohol are added and
- B. finally washed with methylated spirit to achieve transparency
- C. Metallic soaps with frothing agent and free Stearic acid to achieve transparency
- D. Metallic soaps with frothing agent from which glycerine has not been recovered
- E. None of these
Explanation: Transparent soaps are produced by incorporating materials such as alcohol, sugar and glycerine into soap, which reduces crystal formation…
Correct answer: Usually soft soap (made from coconut oil) in which cane sugar & alcohol are added and