Page 31 - Q & A STPM 2022 Chemistry

Chemistry Term 3 STPM Chapter 14 Introduction to Organic Chemistry
14.4 Isomerism: Structural and Stereoisomerism

Section A Multiple-choice Questions

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Question 1
Which of the following is not true for the following molecule?

HO! !CH!CH"CH! !COOH
&
CHO

A It has cis-trans isomers.
B It is optically active.
C It is soluble in water.
D It has more than one functional group.

Answer: C
The presence of three hydrophobic benzene rings renders the compound
insoluble in water although the !OH and !COOH groups can form
hydrogen bonds with water molecules.

The chiral centre and the various functional groups are shown below:
*
HO! !CH!CH"CH! !COOH
&
CHO

The presence of the C"C double bond (where no two identical atoms/groups
are attached to the unsaturated carbon atoms) enables it to exhibit cis-trans
isomerism.
COOH
H H H
C"C C"C CHO
HO! !CH HO! !CH H
& COOH &
CHO
Term
Cis–isomer Trans–isomer
3

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