Paper 1 Q25 — Forces between two different polymers

Intermolecular forces — no H-bonding without N–H/O–H; saturated chains cannot form new covalent bonds

What the examiners said

“Many candidates selected the presence of hydrogen bonds or covalent bonds between the two polymers even though there are no −NH or −OH groups present… and poly(ethene) is a saturated structure so would be unable to make covalent bonds.”

Try the question

An adhesive of poly(methyl cyanoacrylate) sticks to a saturated poly(ethene) surface. What intermolecular attraction acts between the two polymers?

Examiner report: “Candidates wrongly proposed H-bonds/covalent bonds despite no −NH/−OH and a saturated poly(ethene).”

Explore — which force can actually form?

Inspect each polymer’s groups at the interface, then test each proposed interaction. Only the ones whose requirements are met light up.

Proposed interaction: id\u2013id / pd\u2013id

Only dispersion / dipole-induced-dipole forces survive the checklist. The trap answers all assume groups or reactivity that simply are not present.

Original reconstruction inspired by the misconceptions described in the Singapore-Cambridge GCE A-Level H1 Chemistry 8873 November 2023 Examiner Report. Not the actual examination question. For classroom exploration.

Made by lookang, using Claude Fable 5. More resources: iwant2study.org