JPJC 2026 Intro to Organic Chemistry and Isomerism Assignment Answer

2026 JPJC JC1 H2 Chemistry (9476) 1 [Turn Over JURONG PIONEER JUNIOR COLLEGE 2026 JC1 H2 Chemistry (9476) Topical Assignment Topic 8: Introduction to Organic Chemistry and Isomerism Name : __________________________________________ 10 Class : 26S ___ Date : ____________ Duration : 15 minutes 1 Citronellol and compound X are two organic compounds that are found in some perfumes and scents of flowers. C C C C C C C CH3 CH3H H H H H CH3 H H H OH H H citronellol C C C C C C C CH2OH CH3CH3 H H H H H H H H H H H geraniol 12 (a) Compound X is a constitutional isomer of citronellol. Explain what is meant by constitutional isomerism. Constitutional isomerism is exhibited by compounds with the same molecular formula but different structural formulae. [1] [1] (b) Name the functional groups present in both citronellol and compound X. primary alcohol and alkene [1] [1] (c) Draw the skeletal structure of citronellol. OH [1] [1] (d) State the types of hybridisation and sketch the shapes of the hybrid orbitals of carbon atom C−1 and C−2 of compound X. Atom Type of hybridisation Shape of hybrid orbitals C−1 sp3 (✓) [1] C−2 sp2 (✓) Both correct [1] [1] [3] compound X

2026 JPJC JC1 H2 Chemistry (9476) 2 (e) Both citronellol and compound X exhibit stereoisomerism. State the type of stereoisomerism exhibited by each compound and draw appropriate diagrams to illustrate the stereoisomerism exhibited. Type of stereoisomerism: enantiomerism (✓) Diagrams: a pair of enantiomers (or non-superimposable mirror images) C CH2 Br H CH2CH2CH=C(CH3)2 CH2 OH C CH2 BrH CH2CH2CH=C(CH3)2 CH2 OH * * 2-3 (✓) = [1]; 4 (✓) = [2] Type of stereoisomerism: cis–trans isomerism (✓) Diagrams: C C CH3 CH2(CH2)3CH3CH3 CH2OH C C CH3 CH2(CH2)3CH3 CH3 CH2OH trans-isomercis-isomer 2-4 (✓) = [1]; 5 (✓) = [2] [4] [Total: 10] CH3 CH3 CH3 CH3 (✓*) (✓*) (✓) (✓**) (✓**) (✓) (✓) * *must show • 3D tetrahedral shape at chiral C • correct bond linkages **must show • trigonal planar at >C=C< • correct bond linkages compound X non-superimposable mirror images