AQA A-Level Chemistry Paper 3, 2019: Question 28

1 mark · Easy difficulty · Multiple Choice

Identify which polymer features hydrogen bonding between its chains from Kevlar, Polythene, PVC, and Terylene.

Practise this question

Question

Question 28 asks: 'Which polymer has hydrogen bonding between its chains?' It provides four multiple-choice options: A Kevlar, B Polythene, C PVC, and D Terylene, each with a response box next to it. Total marks given is 1 mark.
Question text

28 Which polymer has hydrogen bonding between its chains?

[1 mark]

A Kevlar

B Polythene

C PVC

D Terylene

Mark scheme

Show the mark scheme Mark scheme for Question 28 shows the correct answer is option A, awarded 1 mark.

28 A 1

How to answer it

AQA A-Level Chemistry • Polymers & Bonding

Intermolecular Forces Between Polymer Chains

What this question tests

  • Identification of repeating functional groups in condensation and addition polymers.
  • Understanding the fundamental structural criteria required for hydrogen bonding (a hydrogen atom covalently bonded to N, O, or F, interacting with a lone pair on another electronegative atom).
  • Distinguishing between secondary forces in polyamides, polyesters, and polyalkenes.

Question 28

Multiple Choice • 1 Mark

Which polymer has hydrogen bonding between its chains?

  • A Kevlar
  • B Polythene
  • C PVC
  • D Terylene

✅ Correct Answer

A — Kevlar

Mark Scheme Breakdown:
• Selecting option A awards 1 mark.

Kevlar is an aromatic polyamide. The repeating unit contains secondary amide linkages ( -CO-NH- ). The strongly polarised N-H bond allows extensive hydrogen bonds to form between the N-H group of one chain and the lone pair of electrons on the carbonyl oxygen ( C=O ) of an adjacent chain.

💡 Key Knowledge: Comparing the Options

  • A (Kevlar): Polyamide made from benzene-1,4-diamine and benzene-1,4-dicarboxylic acid. Possesses N-H donor and C=O acceptor → Hydrogen bonding.
  • B (Polythene): Pure non-polar polyalkene hydrocarbon, -[CH₂-CH₂]- → Only weak Van der Waals (induced dipole-dipole) forces.
  • C (PVC): Poly(chloroethene), containing polar C-Cl bonds → Permanent dipole-dipole and Van der Waals forces, but no H directly bonded to N, O, or F.
  • D (Terylene): Polyester formed from benzene-1,4-dicarboxylic acid and ethane-1,2-diol. Contains ester linkages ( -COO- ) → Has polar C=O groups (acceptors), but no H bonded to O to act as donors. Thus, only permanent dipole-dipole forces, NOT hydrogen bonding.

❌ Common Misconceptions & Traps

  • Confusing Terylene with Hydrogen Bonding: Many students see oxygen atoms in Terylene's ester linkages and incorrectly assume it forms hydrogen bonds. Remember: an ester has no hydrogen atom attached directly to an electronegative atom ( O-H ). It can accept H-bonds from water, but polymer chains cannot form hydrogen bonds to each other.
  • Assuming PVC forms H-bonds: Chlorine is electronegative, but C-H···Cl interactions are not strong enough to meet the formal definition of hydrogen bonds in AQA A-Level Chemistry.

🧠 Exam Technique: Rapid Identification

  • Rule of thumb for polymer interactions:
    • Polyamides (Kevlar, Nylon 6,6, proteins) → Hydrogen bonds (via -CONH- ).
    • Polyesters (Terylene / PET) → Permanent dipole-dipole (via -COO- ).
    • Addition polymers (Polythene, Polypropene) → Van der Waals only.
  • When you see "hydrogen bonding between chains", immediately scan for polyamides containing the -NH- moiety!

Topics

Organic Chemistry · Physical Chemistry · 3.1.3 Bonding · 3.3.12 Polymers

Question and mark scheme from the AQA A-Level Chemistry examination, Paper 3, 2019. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.