Level 1 — RecognitionPolymers

Polymers

⏱ 20 minutes30 marksprintable — key stays hidden on paper

Level 1 Test Paper — Recognition

Time Limit: 20 minutes Total Marks: 30

Section A — Multiple Choice Questions (1 mark each)

Choose the ONE correct option.

Q1. Which of the following is a natural polymer? (a) PVC (b) Nylon-6,6 (c) Cellulose (d) Bakelite

Q2. Teflon (PTFE) is an addition polymer of: (a) Tetrafluoroethene (b) Vinyl chloride (c) Propene (d) Styrene

Q3. Which polymer is a thermosetting plastic? (a) Polyethene (b) Bakelite (c) Polystyrene (d) PVC

Q4. The monomers of nylon-6,6 are: (a) Caprolactam only (b) Adipic acid + hexamethylenediamine (c) Terephthalic acid + ethylene glycol (d) Phenol + formaldehyde

Q5. Ziegler–Natta catalyst is used in which type of polymerization? (a) Free-radical (b) Cationic (c) Coordination (d) Step-growth

Q6. The monomer of polyacrylonitrile (Orlon) is: (a) $CH_2=CH-CN$ (b) $CH_2=CH-Cl$ (c) $CH_2=CH-C_6H_5$ (d) $CH_2=C(CH_3)COOCH_3$

Q7. Which pair of polymers is used as aerospace / high-strength materials? (a) PVC and PMMA (b) Kevlar and Nomex (c) Polyethene and PET (d) Bakelite and Teflon

Q8. The polydispersity index (PDI) of a perfectly monodisperse polymer equals: (a) 0 (b) 0.5 (c) 1 (d) 2

Q9. Which of the following is a biodegradable polymer? (a) Polystyrene (b) PHBV (c) PVC (d) Teflon

Q10. Terylene (PET) is formed by condensation of ethylene glycol with: (a) Adipic acid (b) Terephthalic acid (c) Phthalic acid (d) Caprolactam

Section B — Matching (2 marks each; ½ mark per correct pair)

Q11. Match the polymer with its monomer/repeat unit:

Polymer		Monomer
(i) PVC		(A) Styrene
(ii) Polystyrene		(B) Methyl methacrylate
(iii) PMMA		(C) Vinyl chloride
(iv) Polypropylene		(D) Propene

Q12. Match the polymer with its classification/use:

Polymer		Feature/Use
(i) Nomex		(A) Fire-resistant fabric
(ii) Bakelite		(B) Body armour, parachutes
(iii) Kevlar		(C) Melamine-formaldehyde crockery analog (thermoset)
(iv) Epoxy resin		(D) Composite matrix in CFRP

Section C — True / False with justification (2 marks each: 1 for T/F, 1 for reason)

Q13. All addition polymers are formed without loss of any small molecule.

Q14. Nylon-6 and nylon-6,6 are both made from a single type of monomer.

Q15. For any real polymer sample, the weight-average molecular weight ( $\overline{M}_w$ ) is always greater than or equal to the number-average molecular weight ( $\overline{M}_n$ ).

Q16. Free-radical polymerization of ethene is an example of step-growth polymerization.

Q17. Nylon-2-nylon-6 is a biodegradable polymer.

Q18. Thermosetting polymers can be repeatedly softened by heating and remoulded.

Answer keyMark scheme & solutions

Section A (10 marks)

Q1. (c) Cellulose — a natural polysaccharide from plants; the others are synthetic. (1)

Q2. (a) Tetrafluoroethene — PTFE = $-(CF_2-CF_2)_n-$ , from $CF_2=CF_2$ . (1)

Q3. (b) Bakelite — a cross-linked phenol-formaldehyde network; the rest are linear thermoplastics. (1)

Q4. (b) Adipic acid + hexamethylenediamine — condensation gives the "6,6" amide. (1)

Q5. (c) Coordination — Ziegler–Natta $(TiCl_4/Al(C_2H_5)_3)$ gives stereoregular polymers. (1)

Q6. (a) $CH_2=CH-CN$ (acrylonitrile). (1)

Q7. (b) Kevlar and Nomex — aromatic polyamides (aramids) used in armour and fire-resistant gear. (1)

Q8. (c) 1 — PDI $=\overline{M}_w/\overline{M}_n=1$ when all chains are identical. (1)

Q9. (b) PHBV — poly(3-hydroxybutyrate-co-3-hydroxyvalerate), a biodegradable polyester. (1)

Q10. (b) Terephthalic acid — PET = poly(ethylene terephthalate). (1)

Section B (4 marks)

Q11. (i)–C, (ii)–A, (iii)–B, (iv)–D. (½ each = 2)

Q12. (i)–A, (ii)–C, (iii)–B, (iv)–D. (½ each = 2)

Q13. TRUE. In addition (chain-growth) polymerization, monomers with C=C simply add across the double bond; no small molecule is eliminated, so the polymer's empirical formula matches the monomer. (T/F 1 + reason 1)

Q14. FALSE. Nylon-6 is made from a single monomer (caprolactam), but nylon-6,6 needs two monomers (adipic acid + hexamethylenediamine). The statement is false because it wrongly claims both use one monomer type. (1 + 1)

Q15. TRUE. By definition $\overline{M}_w \geq \overline{M}_n$ , with equality only for a monodisperse sample; higher-mass chains are weighted more heavily in $\overline{M}_w$ , so PDI $\geq 1$ . (1 + 1)

Q16. FALSE. Free-radical polymerization of ethene is a chain-growth (addition) process (initiation–propagation–termination), not step-growth. Step-growth involves reaction between bifunctional monomers with elimination. (1 + 1)

Q17. TRUE. Nylon-2-nylon-6 is an alternating copolymer of glycine and amino caproic acid; the amide linkages and hydrolysable structure make it biodegradable. (1 + 1)

Q18. FALSE. That property describes thermoplastics. Thermosetting polymers form permanent cross-links on heating and cannot be re-softened/remoulded. (1 + 1)

[
  {"claim": "Monodisperse PDI = Mw/Mn = 1", "code": "Mn=100; Mw=100; PDI=Mw/Mn; result = (PDI==1)"},
  {"claim": "For a 2-chain sample masses 100 and 300 (equal number), Mw>=Mn", "code": "n1=1; n2=1; M1=100; M2=300; Mn=(n1*M1+n2*M2)/(n1+n2); Mw=(n1*M1**2+n2*M2**2)/(n1*M1+n2*M2); result = bool(Mw>=Mn)"},
  {"claim": "PTFE repeat unit carbon-fluorine ratio is 1:2 (from CF2CF2)", "code": "C=2; F=4; result = (F/C==2)"},
  {"claim": "Nylon-6,6 requires two distinct monomers", "code": "monomers=2; result = (monomers==2)"}
]