Free Chemical Process Principles MCQs with Answers

• A. Carbon atoms in the linear polymer chain
• B. Carbon atoms in the ring
• C. Nitrogen atoms in the ring
• D. Hydrogen atoms in the ring

Explanation: The “6” in nylon-6 refers to the six carbon atoms contributed by each caprolactam molecule, represented by the six carbons in the…

• A. Employs addition polymerisation
• B. Employs condensation polymerisation
• C. Is a monomer
• D. Is an abrasive material

Explanation: Phenol and formaldehyde react by condensation polymerisation, forming Bakelite with elimination of small molecules such as water.

• A. Bakelite
• B. Melamine polymer
• C. Poly-methyl-methacrylate (PMMA)
• D. None of these

Explanation: Bakelite and melamine-formaldehyde are condensation polymers because their formation eliminates small molecules.

• A. Nylon
• B. Polyester
• C. Polypropylene
• D. Polyacrylonitrile

Explanation: Polyacrylonitrile is comparatively amorphous among the listed fibre-forming polymers, whereas nylon, polypropylene and polyester generally…

• A. Catalytic dehydrogenation of ethyl benzene
• B. Dehydration of ethyl alcohol followed by hydrogenation
• C. Reacting ethylene oxide with acetaldehyde
• D. Fermentation of starch

Explanation: Industrial styrene is produced mainly by catalytic dehydrogenation of ethylbenzene: C6H5CH2CH3 yields C6H5CH=CH2 plus hydrogen.

• A. Low density
• B. High density
• C. Cross-linked
• D. Linear low density

Explanation: High-density polythene is more prone to environmental stress cracking because its greater crystallinity and stiffness allow cracks to…

• A. Micro-molecules
• B. None of these
• C. Sub-micromolecules
• D. Macromolecules

Explanation: Polymers consist of very long chains made from many repeating units, giving them extremely high molecular masses.

• A. Are cross-linked molecules
• B. Soften on application of heat
• C. Are solvent soluble
• D. None of these

Explanation: Thermosetting polymers develop a permanent three-dimensional cross-linked network during curing.

• A. Polyisoprene
• B. None of these
• C. Nitrile-butadiene
• D. Neoprene

Explanation: Polyisoprene, neoprene and nitrile-butadiene rubber are all elastomers because they can undergo large reversible stretching.

• A. 85
• B. 135
• C. 165
• D. 205

Explanation: High-density polythene softens at approximately 135°C, reflecting its relatively high crystallinity and melting range.

• A. Emulsion polymerisation
• B. Suspension polymerisation
• C. Solution polymerisation
• D. Bulk polymerisation

Explanation: SBR is commonly produced by free-radical emulsion polymerisation of styrene and butadiene in an aqueous medium.

• A. Perspex
• B. Nylon-66
• C. Polystyrene
• D. Bakelite

Explanation: Nylon-66 is made from hexamethylene diamine and adipic acid, and adipic acid is therefore one of its key intermediates.

• A. Thermosetting resin
• B. Polyamide
• C. Polyester
• D. None of these

Explanation: Nylon-6 contains repeating amide linkages, formed by polymerisation of caprolactam or 6-aminohexanoic acid.

• A. Polycarbonates
• B. Polytetrafluroethylene (PTFE)
• C. Polymethyl methacrylate (PMMA)
• D. Phenolic resins

Explanation: Plexiglass or Lucite is polymethyl methacrylate, whose clear amorphous structure gives high optical transparency.

• A. Teflon
• B. Bakelite
• C. SBR
• D. PVC

Explanation: Rexine is artificial leather made by coating fabric with polyvinyl chloride, often followed by embossing to imitate leather.

• A. Hexamethylene diamine and adipic acid
• B. Adipic acid and methyl amine
• C. Vinyl chloride and formaldehyde
• D. None of these

Explanation: Nylon-66 is a condensation polyamide formed from a six-carbon diamine, hexamethylene diamine, and a six-carbon diacid, adipic acid.

• A. Rosin
• B. Shellac
• C. Amber
• D. Copal

Explanation: Shellac is a natural thermoplastic resin secreted by the lac insect, so it is a product of animal life.

• A. Nylon-66
• B. Polyester
• C. Teflon
• D. Bakelite

Explanation: Teflon is formed by chain-growth addition polymerisation of tetrafluoroethylene through successive radical additions.

• A. An isomer of natural rubber
• B. Soft & tacky at room temperature
• C. A thermosetting resin
• D. Recovered by coagulation of rubber latex

Explanation: Gutta percha is the trans isomer of natural rubber, whereas ordinary natural rubber is mainly the cis form.

• A. Polyamide
• B. Unsaturated polyesters
• C. Saturated polyesters
• D. Polyacrylonitrile

Explanation: Unsaturated polyesters generally form cross-linked thermosetting networks, so they cannot be readily softened and drawn into fibres.