Free Chemical Process Principles MCQs with Answers

• A. Gypsum
• B. Feldspar
• C. Galena
• D. Bauxite

Explanation: Bauxite is the principal commercial ore of aluminium and supplies the alumina needed for alum manufacture.

• A. 1 atm & 100°C
• B. 5 atm & 275°C
• C. 100 atm & 500°C
• D. 50 atm & 1000°C

Explanation: Ethylene is directly oxidised over a silver catalyst at moderate pressure and about 250 to 300°C to form ethylene oxide.

• A. 80
• B. 90
• C. 98
• D. 100

Explanation: A four-pass sulphur dioxide converter achieves approximately 98% overall conversion to sulphur trioxide.

• 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.

• 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…

• 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.

• 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.

• 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.

• 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.

• 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.

• 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…

• 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.

• 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.

• 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.

• A. Alum
• B. Washing soda
• C. Calcium carbide
• D. Soda ash

Explanation: The Leblanc process historically produced sodium carbonate, known commercially as soda ash.

• A. Starch
• B. Maltose
• C. Sucrose
• D. Glucose

Explanation: Starch is a polysaccharide made of many glucose units joined in long chains.

• 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.

• 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…

• 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.

• 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.