Free Chemical Process Principles MCQs with Answers

• A. Improve its impact strength
• B. Improve its elasticity
• C. Prevent its thermal degradation
• D. Reduce the melt viscosity & glass transition temperature

Explanation: PVC can release hydrogen chloride and undergo autocatalytic degradation when heated, causing discoloration and loss of properties.

• A. Wet tear and bursting strength
• B. Folding endurance
• C. Wet rub resistance
• D. All A., B. & C.

Explanation: Amino resins, especially urea-formaldehyde and melamine-formaldehyde resins, improve paper's wet strength, bursting and tear resistance…

• A. Polyhexamethylene adipamide
• B. Poly vinyl chloride
• C. Polystyrene
• D. Low density polythene

Explanation: Low-density polythene, PVC, and polystyrene are formed by addition polymerisation of unsaturated monomers.

• A. PVC
• B. Epoxy polymer
• C. Polystyrene
• D. Polythene

Explanation: Epoxy polymer is normally a cross-linked thermosetting material, so it cannot be repeatedly softened and reshaped by heating.

• A. Adhesion to rubber
• B. Thermal stability
• C. Abrasion resistance
• D. Hardness

Explanation: Nylon-66 has greater chain regularity and generally provides better abrasion resistance than nylon-6.

• A. Caprolactam
• B. Adipic acid and Hexamethylenediamine
• C. Maleic anhydride and Hexamethylenediamine
• D. Sebacic acid and Hexamethylenediamine

Explanation: Nylon-6 is produced by ring-opening polymerisation of caprolactam, a cyclic amide.

• A. Are made by addition polymerisation reaction only
• B. Contain an epoxy group (fig bellow) at the ends of the polymer
• C. Are cross-linked polymers only
• D. Use emulsion polymerisation methods

Explanation: Epoxy resins are commonly made from molecules such as diglycidyl ethers that retain terminal epoxy groups, which later react with curing…

• A. Dacron
• B. Teflon
• C. Melamine resins
• D. None of these

Explanation: Melamine resins are amino-formaldehyde resins formed by reacting melamine with formaldehyde.

• A. Acetylene
• B. Isoprene
• C. Chloroprene
• D. None of these

Explanation: Neoprene is polychloroprene, produced by polymerising chloroprene, also called 2-chloro-1,3-butadiene.

• A. Resorcinol
• B. Phenol
• C. Para-cresol
• D. Melamine

Explanation: Melamine reacts with formaldehyde to form an amino resin, specifically melamine-formaldehyde resin, not a phenolic resin.

• A. DMT
• B. Methyl methacrylate
• C. Butadiene
• D. Tetrafluoroethylene

Explanation: Perspex is polymethyl methacrylate, formed by polymerising methyl methacrylate monomer.

• A. Rigid foam
• B. Thermosetting polymer
• C. Engineering plastic
• D. Spongy rubberEngineering & Technology

Explanation: ABS is classified as an engineering plastic because its styrene-acrylonitrile matrix combined with rubber gives good impact strength…

• A. Carbon
• B. Magnesium
• C. Thiokol
• D. Alkylated diphenyl amine

Explanation: Alkylated diphenyl amines act as antioxidants by inhibiting oxidation reactions in rubber caused by heat, light and ozone.

• A. 50°C and 3 - 4 kg/cm2
• B. 50°C and 1 kgf/cm2
• C. 250°C and 10 kgf/cm2
• D. 250°C and 1 kgf/cm2

Explanation: Hot SBR is produced by emulsion polymerisation at about 50°C, commonly under a gauge pressure of roughly 3 to 4 kgf/cm².

• A. Polyamide
• B. Polyester
• C. Polystyrene
• D. Polyacrylonitrile

Explanation: Glyptal is an alkyd resin made by reacting glycerol with phthalic anhydride, so it belongs to the polyester family.

• A. Lignin
• B. Gelatine
• C. Starch
• D. Cellulose

Explanation: Cotton fibre is composed mainly of cellulose, a linear polysaccharide made from β-glucose units.

• A. Less brittle than thermosetting resins
• B. Cannot be reclaimed from waste
• C. Permanent setting resins
• D. Remain hard as long as they are hot

Explanation: Thermoplastics soften on heating and harden on cooling, so they can generally be remoulded and recycled; they are also usually less…

• A. Employs a pressure of 30 kgf/cm2
• B. Achieves an yield of 95-98% based on ethylene
• C. Produces very low density polythene
• D. Does not use any catalyst for polymerisation

Explanation: The low-pressure Ziegler process uses a catalyst and converts ethylene with a high yield, commonly about 95 to 98 percent.

• A. Polysulphide rubber
• B. Spandex fibre
• C. Vulcanite or ebonite
• D. Epoxy resin

Explanation: Vulcanite, or ebonite, is hard rubber with extensive sulphur cross-linking, making it rigid and practically non-elastic.

• A. Fibrous
• B. Plastic
• C. Resinous
• D. Rubbery

Explanation: Buna-S is styrene-butadiene rubber, a synthetic elastomer made by copolymerising butadiene with styrene.