60 free MCQs on Polymers with worked answers and explanations. Large molecules made of repeating monomer units. Covers addition and condensation polymerisation, natural and synthetic polymers (nylon, PVC, Bakelite, natural rubber), and their real-world industrial applications.
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Addition polymerisation simply links monomers containing a double bond with nothing left over, while condensation polymerisation joins two different monomers through a reaction (often forming an ester or amide bond) that releases a small molecule like water at each step.
Q1.
What is a polymer?
Answer: A. A large molecule made of repeating smaller units
Why: Polymers are macromolecules composed of many repeating monomer units linked by covalent bonds.
Q2.
What is the small repeating unit of a polymer called?
Answer: A. Monomer
Why: A monomer is the small repeating unit that polymerises to form the polymer chain.
Q3.
Which polymer is used to make plastic bottles (PET)?
Answer: A. Polyethylene terephthalate
Why: PET (polyethylene terephthalate) is the polymer used to make clear plastic bottles.
Q4.
Nylon is an example of which type of polymer?
Answer: A. Polyamide
Why: Nylon is a polyamide; its monomers are joined by amide (-CO-NH-) linkages.
Q5.
Which polymer is commonly known as Teflon?
Answer: A. Polytetrafluoroethylene (PTFE)
Why: Teflon is the brand name for PTFE, a non-stick polymer used in cookware coatings.
Q6.
Natural rubber is a polymer of:
Answer: A. Isoprene
Why: Natural rubber is a polymer of 2-methylbuta-1,3-diene (isoprene).
Q7.
PVC stands for:
Answer: A. Polyvinyl chloride
Why: PVC (polyvinyl chloride) is widely used for pipes, cables, and packaging.
Q8.
Which polymer is used to make ropes and carpets?
Answer: A. Polypropylene
Why: Polypropylene is durable and resistant, making it suitable for ropes, carpets, and furniture.
Q9.
Thermoplastic polymers can be:
Answer: A. Softened and reshaped on heating
Why: Thermoplastics (like polyethylene, PVC) soften reversibly on heating and can be remoulded.
Q10.
Thermosetting polymers:
Answer: A. Set permanently on heating and cannot be reshaped
Why: Thermosetting polymers (like Bakelite, epoxy) form irreversible cross-links on curing and cannot be remelted.
Q11.
Bakelite is made from:
Answer: A. Phenol and formaldehyde
Why: Bakelite is a thermosetting polymer made by condensation of phenol with formaldehyde.
Q12.
The process of converting monomers into polymers is called:
Answer: A. Polymerisation
Why: Polymerisation is the chemical process in which monomers combine to form long polymer chains.
Q13.
Which polymer is used to make CDs, DVDs, and eyeglass lenses?
Answer: A. Polycarbonate
Why: Polycarbonate is optically clear, impact-resistant, and used for CDs, DVDs, and eyeglass lenses.
Q14.
Dacron (Terylene) is a:
Answer: A. Polyester
Why: Dacron/Terylene is polyethylene terephthalate (PET), a polyester polymer used in fibre form for clothing.
Q15.
Vulcanisation of rubber involves adding:
Answer: A. Sulfur
Why: Vulcanisation uses sulfur to create cross-links between rubber chains, improving strength and elasticity.
Q16.
Which polymer is used in making bulletproof vests?
Answer: A. Kevlar (poly-p-phenylene terephthalamide)
Why: Kevlar is an aromatic polyamide with extremely high tensile strength, used in bulletproof vests.
Q17.
Buna-S is a copolymer of:
Answer: A. Butadiene and styrene
Why: Buna-S (SBR) is a synthetic rubber made from butadiene and styrene.
Q18.
Addition polymers are formed by:
Answer: A. Repeated addition of monomers with double bonds, no byproduct
Why: Addition polymerisation occurs with monomers containing C=C; no small molecule is released as byproduct.
Q19.
Condensation polymers are formed with loss of:
Answer: A. Small molecules like water or HCl
Why: Condensation polymerisation releases small molecules (water, methanol, HCl) as each bond forms.
Q20.
Which polymer is used in non-stick cookware?
Answer: A. Teflon (PTFE)
Why: Teflon (PTFE) has extremely low surface energy and is used as the non-stick coating in cookware.
Q21.
What is the degree of polymerisation?
Answer: A. Number of monomer units in a polymer chain
Why: The degree of polymerisation (n) is the number of repeating monomer units in one polymer chain.
Q22.
Nylon-6,6 is made from:
Answer: A. Hexamethylenediamine and adipic acid
Why: Nylon-6,6 is a condensation polymer of hexamethylenediamine (6 C) and adipic acid (6 C).
Q23.
Nylon-6 is made from:
Answer: A. Caprolactam (ring-opening polymerisation)
Why: Nylon-6 is formed by ring-opening polymerisation of caprolactam.
Q24.
Buna-N (Nitrile rubber) is a copolymer of:
Answer: A. Butadiene and acrylonitrile
Why: Buna-N (NBR) is formed from butadiene and acrylonitrile; it is oil-resistant.
Q25.
High-density polyethylene (HDPE) is produced using:
Answer: A. Ziegler-Natta catalyst
Why: HDPE is produced by Ziegler-Natta coordination polymerisation, giving a highly linear, dense structure.
Q26.
Low-density polyethylene (LDPE) has a:
Answer: A. Branched chain structure
Why: LDPE has many branches due to free-radical polymerisation, leading to lower density and flexibility.
Q27.
Which polymer is formed by ring-opening polymerisation?
Answer: A. Nylon-6
Why: Nylon-6 is formed by ring-opening of caprolactam (a cyclic amide), unlike Nylon-6,6 which is a condensation polymer.
Q28.
What type of linkage connects monomers in polyesters?
Answer: A. Ester bond (-COO-)
Why: Polyesters contain ester linkages formed by reaction of diol with dicarboxylic acid.
Q29.
Glyptal is a polyester made from:
Answer: C. Glycerol and phthalic acid
Why: Glyptal (alkyd resin) is formed from glycerol (a triol) and phthalic acid, giving a cross-linked polyester.
Q30.
What is a copolymer?
Answer: A. Polymer made from two or more different monomers
Why: Copolymers are formed when two or more different monomers polymerise together, giving varied properties.
Q31.
Chain-growth polymerisation involves:
Answer: A. Addition of monomers to a growing reactive chain end
Why: In chain-growth (addition) polymerisation, a reactive chain end (radical, cation, or anion) adds monomer units one at a time.
Q32.
Melamine-formaldehyde resin is used in:
Answer: A. Unbreakable crockery and laminates
Why: Melamine-formaldehyde thermosetting resin is used for unbreakable dishes, laminates, and flooring.
Q33.
Which property of Teflon makes it non-stick?
Answer: A. Very low surface energy due to strong C-F bonds
Why: The extremely strong C-F bonds in PTFE give it the lowest coefficient of friction, making surfaces non-stick.
Q34.
What are the monomers of Dacron (Terylene)?
Answer: A. Ethylene glycol and terephthalic acid
Why: Dacron is formed by condensation polymerisation of ethylene glycol and terephthalic acid.
Q35.
Silicone polymers have a backbone of:
Answer: A. -Si-O-Si-O-
Why: Silicone polymers (polysiloxanes) have an inorganic silicon-oxygen backbone, giving them thermal stability.
Q36.
Which polymer is biodegradable?
Answer: A. PHBV (polyhydroxybutyrate-co-valerate)
Why: PHBV is a biodegradable polymer produced naturally by bacteria, used in packaging and medical devices.
Q37.
ABS plastic (Acrylonitrile Butadiene Styrene) is a:
Answer: A. Terpolymer
Why: ABS is a terpolymer made from three monomers: acrylonitrile, butadiene, and styrene.
Q38.
What is the role of the initiator in free-radical polymerisation?
Answer: A. Generates free radicals to start the chain reaction
Why: Initiators (e.g., benzoyl peroxide) decompose to generate free radicals that begin the polymerisation chain.
Q39.
Cross-linking in a polymer:
Answer: A. Increases rigidity and reduces solubility
Why: Cross-links (covalent bonds between chains) prevent chain movement, increasing hardness, rigidity, and reducing solubility.
Q40.
Which monomer is used to make polystyrene?
Answer: A. Styrene (vinylbenzene)
Why: Polystyrene is made by addition polymerisation of styrene (C6H5-CH=CH<sub>2</sub>).
Q41.
In the Ziegler-Natta catalyst system, which two components are essential?
Answer: A. TiCl<sub>4</sub> and Al(C<sub>2</sub>H<sub>5</sub>)<sub>3</sub>
Why: Ziegler-Natta catalyst consists of a transition metal halide (TiCl<sub>4</sub>) and an organoaluminium compound (triethylaluminium).
Q42.
Tacticity of a polymer refers to:
Answer: A. Spatial arrangement of pendant groups along the chain
Why: Tacticity describes the regularity of substituent placement: isotactic (all same side), syndiotactic (alternating), atactic (random).
Q43.
Isotactic polypropylene differs from atactic polypropylene in that it is:
Answer: A. Highly crystalline and has higher melting point
Why: Isotactic PP has regular chain geometry, allowing it to crystallise; atactic PP is amorphous and rubbery.
Q44.
Step-growth polymerisation requires bifunctional monomers. High molecular weight is achieved only at:
Answer: A. Very high conversion (>99%) of functional groups
Why: Carothers equation shows Xn = 1/(1-p); only at p>0.99 do you get degree of polymerisation >100.
Q45.
PHBV is a biodegradable polymer. The two monomer units present are:
Answer: A. 3-Hydroxybutyrate and 3-hydroxyvalerate
Why: PHBV is a copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate produced by bacteria.
Q46.
The glass transition temperature (Tg) of a polymer is the temperature at which:
Answer: A. The amorphous regions transition from glassy to rubbery state
Why: Below Tg, polymer chains are immobile (glassy); above Tg, they become mobile (rubbery). It applies to amorphous regions.
Q47.
Living polymerisation is characterised by:
Answer: A. No termination or transfer reactions, allowing controlled molecular weight
Why: In living polymerisation, chains grow without termination; it gives narrow molecular weight distributions and allows block copolymer synthesis.
Q48.
Kevlar has exceptional strength because:
Answer: A. Extensive hydrogen bonding between amide groups in parallel chains
Why: Kevlar chains are perfectly aligned and form extensive intermolecular hydrogen bonds between amide NH and C=O groups.
Q49.
The polydispersity index (PDI) of an ideal living polymer is:
Answer: A. Close to 1.0
Why: PDI = Mw/Mn; ideal living polymerisation gives all chains of nearly equal length, so PDI approaches 1.0.
Q50.
Which type of polymerisation is used to make epoxy resins?
Answer: A. Ring-opening polymerisation of epoxide monomers
Why: Epoxy resins are formed by ring-opening of epoxide (oxirane) groups with amines or anhydrides.
Q51.
Neoprene (polychloroprene) is a synthetic rubber used for its:
Answer: A. Resistance to oil, weather, and ozone
Why: Neoprene is resistant to oil, ozone, and weathering, making it valuable for wetsuits, hoses, and cables.
Q52.
Which polymer contains a benzene ring in its main chain?
Answer: A. Polycarbonate
Why: Polycarbonate [C6H4-C(CH<sub>3</sub>)2-C6H4-O-CO-O] has bisphenol A residues with benzene rings in the backbone.
Q53.
The termination step in free-radical polymerisation occurs by:
Answer: A. Combination or disproportionation of two radical chain ends
Why: Two radical chain ends can combine (coupling) or disproportionate (H transfer) to terminate the chain.
Q54.
Which polymer is formed by coordination polymerisation of propylene?
Answer: A. Isotactic polypropylene
Why: Ziegler-Natta (coordination) polymerisation of propylene gives primarily isotactic PP with high crystallinity and melting point.
Q55.
Cellulose cannot be digested by humans because:
Answer: A. Humans lack beta-glucosidase enzyme to break beta-1,4 glycosidic bonds
Why: Humans lack cellulase (beta-1,4-glucanase); ruminants have microbes that produce it to digest cellulose.
Q56.
The Carothers equation relates degree of polymerisation (Xn) to conversion (p) as:
Answer: A. Xn = 1/(1-p)
Why: Carothers equation for linear condensation polymers: Xn = 1/(1-p), where p is the fraction of functional groups reacted.
Q57.
Polyurethanes are formed by reaction of a diisocyanate with:
Answer: A. Diol (a dihydroxy compound)
Why: Polyurethanes are made by polyaddition of diisocyanates (R-N=C=O) with diols, forming urethane linkages (-NH-CO-O-).
Q58.
Block copolymers consist of:
Answer: A. Long sequences of one monomer followed by long sequences of another
Why: Block copolymers have distinct segments (blocks) of different monomers, e.g., A-A-A-A-B-B-B-B.
Q59.
The number-average molecular weight (Mn) is defined as:
Answer: A. Total weight of polymer / total number of molecules
Why: Mn = sum(Ni * Mi) / sum(Ni), where Ni is the number of chains with molecular weight Mi.
Q60.
Which method gives the weight-average molecular weight (Mw) of a polymer?
Answer: A. Light scattering
Why: Static light scattering directly measures Mw because larger chains scatter more light (proportional to weight fraction).