DP Chemistry (first assessment 2025)

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Question 22M.2.HL.TZ1.5a(v)

Date	May 2022	Marks available	[Maximum mark: 1]	Reference code	22M.2.HL.TZ1.5a(v)
Level	HL	Paper	2	Time zone	TZ1
Command term	Identify	Question number	a(v)	Adapted from	N/A

a(v).

[Maximum mark: 1]

22M.2.HL.TZ1.5a(v)

(a(v))

Identify the isomer of Compound B that exists as optical isomers (enantiomers).

[1]

Markscheme

butan-2-ol/CH₃CH(OH)C₂H₅ ✔

Examiners report

Mediocre performance; some identified 2-methylpropan-1-ol or -2-ol, instead butan-2-ol/CH₃CH(OH)C₂H₅ as the isomer that exists as an optical isomer.

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).