DP Chemistry (first assessment 2025)

Question 20N.1A.HL.TZ0.40

Date	November 2020	Marks available	[Maximum mark: 1]	Reference code	20N.1A.HL.TZ0.40
Level	HL	Paper	1A	Time zone	TZ0
Command term	Deduce, Determine	Question number	40	Adapted from	N/A

40.

[Maximum mark: 1]

20N.1A.HL.TZ0.40

Which compound with the molecular formula $C_{4} H_{8} O$ has this high resolution ${}_{1}H NMR$ ?

From: libretexts.org. Courtesy of Chris Schaller, Professor (Chemistry)
at College of Saint Benedict/Saint John’s University.

A. but-3-en-2-ol, ${CH}_{2} = CHCH (OH) {CH}_{3}$

B. butanal, ${CH}_{3} {CH}_{2} {CH}_{2} CHO$

C. butanone, ${CH}_{3} {COCH}_{2} {CH}_{3}$

D. but-3-en-1-ol, ${CH}_{2} = {CHCH}_{2} {CH}_{2} OH$

[1]

Markscheme

Examiners report

Just over 50% of candidates could identify the correct compound from high resolution 1H NMR data. The question had a relatively high discriminatory index.

Syllabus sections

Structure 3. Classification of matter » Structure 3.2—Functional groups: Classification of organic compounds » Structure 3.2.10—Proton nuclear magnetic resonance spectroscopy (1H NMR) gives information on the different chemical environments of hydrogen atoms in a molecule. Interpret 1H NMR spectra to deduce the structures of organic molecules from the number of signals, the chemical shifts, and the relative areas under signals (integration traces).

Question 20N.1A.HL.TZ0.40

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