1. Which amino acid can exist as optical isomers?
A.
B.
C.
D.
(Total 1 mark)
2. How many chiral carbon atoms are present in a molecule of glucose?
A. 1
B. 2
C. 3
D. 4
(Total 1 mark)
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3. Which species will show optical activity?
A. 1-chloropentane
B. 3-chloropentane
C. 1-chloro-2-methylpentane
D. 2-chloro-2-methylpentane
(Total 1 mark)
4. Which compound can exist as optical isomers?
A. CH3CHBrCH3
B. CH2ClCH(OH)CH2Cl
C. CH3CHBrCOOH
D. CH3CCl2CH2OH
(Total 1 mark)
5. Which compound can exist as optical isomers?
A. CH3CHBrCH3
B. CH2BrCHBrCH3
C. CH2BrCHBrCH2Br
D. CHBr2CHBrCHBr2
(Total 1 mar
6. This question is about structural isomers and stereoisomers with the molecular formula C 4H6Cl2.
(a) The compound 1,3-dichlorobut-1-ene can be used to illustrate two types of stereoisomerism. For
each type of stereoisomerism, draw two structures to show the relationship between the two.
two geometrical isomers
two optical isomers
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(4)
(b) Explain the term racemic mixture.
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(1)
(c) Outline how the two optical isomers of 1,3-dichlorobut-1-ene can be distinguished from each other
and from a racemic mixture.
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(3)
(d) 1,3-dichlorocyclobutane exists as geometrical isomers. Draw the 3-dimensional structures of these
isomers.
(2)
(Total 10 marks)
7. (a) There are geometrical isomers of the cyclic compound C4H6Cl2. Draw the structural formula of
two isomers and explain why these two isomers exist.
cis-isomer trans-isomer
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(3)
(b) (i) Draw the structural formulas of two isomers of but-2-ene-1,4-dioic acid.
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(2)
(ii) State and explain which isomer will have a lower melting point.
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(2)
(iii) Describe how the two isomers can be distinguished by a chemical test.
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(2)
(c) Consider the following compounds:
1-chloropentane, 2-chloropentane, 3-chloropentane
(i) Identify the compound which exhibits optical isomerism and draw the structures of the two
isomers.
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(3)
(ii) Describe how these two isomers can be distinguished experimentally.
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(1)
(Total 13 marks)
4
8. The polymer with the repeating unit
H H O
N C C
C H 3
exists as optical isomers.
(i) State a test for optical isomers.
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(ii) Identify the chiral centre in the repeating unit.
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(iii) Draw the two enantiomeric forms of the repeating unit.
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(Total 4 marks)
5
9. Compounds with the molecular formula C3H4Cl2 exist as several structural isomers, some of which are
cyclic. Some of these structural isomers exist as geometric isomers.
(a) Explain why geometrical isomerism is possible in the non-cyclic isomers.
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(1)
(b) Draw the structure of a non-cyclic structural isomer that does not exist as geometric isomers, and
explain why geometrical isomerism is not possible in this compound.
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(2)
(c) 1,3-Dichloropropene exists as geometric isomers. Draw and label the structures of its cis and trans
isomers.
(2)
(d) Draw structures to show the two geometric isomers of 1,2-dichlorocyclopropane.
(2)
(Total 7 marks)
10. (a) Compounds of formula C4H7Cl exhibits both geometrical and optical isomerism.
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(i) Explain why C4H7Cl shows geometrical isomerism.
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(1)
(ii) Draw the cis and trans isomers of C4H7Cl.
(2)
(iii) Draw the structural formula of C4H7Cl that shows only optical isomerism. Show the chiral
carbon atom with “ * ”.
(2)
(b) Explain why 1,2-dichlorocyclopropane has cis and trans isomers. Draw the structural formulas of
the two isomers.
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(3)
(Total 8 marks)
7
11. One of the alcohols containing four carbon atoms exists as optical isomers.
Give the structural formula and name of this alcohol and explain why it exists as optical isomers. Outline
how these two isomers could be distinguished.
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(Total 4 marks)
12. Which compound can exist as optical isomers?
A. H2NCH2COOH
B. CH2ClCH2Cl
C. CH3CHBrI
D. HCOOCH3
(Total 1 mark)
