DP Chemistry (first assessment 2025)

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Question 20N.1A.HL.TZ0.37

Date	November 2020	Marks available	[Maximum mark: 1]	Reference code	20N.1A.HL.TZ0.37
Level	HL	Paper	1A	Time zone	TZ0
Command term	Determine	Question number	37	Adapted from	N/A

37.

[Maximum mark: 1]

20N.1A.HL.TZ0.37

Which molecule has an enantiomer?

A. ${CH}_{3} {CH}_{2} CH (OH) {CH}_{2} {CH}_{3}$

B. ${CH}_{2} (OH) {CH}_{2} {CH}_{2} CH = {CH}_{2}$

C. ${CH}_{3} {CH}_{2} {CH}_{2} CH = CHBr$

D. ${CH}_{3} {CHBrCH}_{2} {CH}_{2} {CH}_{3}$

[1]

Markscheme

D

Examiners report

The majority of candidates could correctly identify the molecule which has an enantiomer.

Syllabus sections

Structure 3. Classification of matter » Structure 3.2—Functional groups: Classification of organic compounds » Structure 3.2.7—Stereoisomers have the same constitution (atom identities, connectivities and bond multiplicities) but different spatial arrangements of atoms. Describe and explain the features that give rise to cis-trans isomerism; recognize it in non-cyclic alkenes and C3 and C4 cycloalkanes. Draw stereochemical formulas showing the tetrahedral arrangement around a chiral carbon. Describe and explain a chiral carbon atom giving rise to stereoisomers with different optical properties. Recognize a pair of enantiomers as non-superimposable mirror images from 3D modelling (real or virtual).