Syllabus Edition

First teaching 2020

Last exams 2024

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An Introduction to A Level Organic Chemistry (A Level Only) (CIE A Level Chemistry)

Exam Questions

2 hours13 questions
1a4 marks

The structural formulae of four different organic compounds are shown in Table 1.1.

Table 1.1

Structural formula IUPAC name
C6H5CH3  
CH3CH2CH2CH2CHO  
CH3NHCH3  
CH3CH(NH2)CO2H  

 

Complete Table 1.1 by writing the systematic name for each compound.

1b1 mark

Draw the fully displayed formula for butanoyl chloride.








butanoyl chloride
1c1 mark

Butanoyl chloride can react with water to form butanoic acid. State the type of mechanism that this reaction involves.

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2a2 marks

This question is about benzene.

Draw the displayed formula for benzene.

2b1 mark

State the bond angle in the planar regular hexagon structure of benzene.

2c1 mark

State the type of hybridisation of the carbon atoms in benzene.

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3a3 marks

This question is about isomerism in different acids.

Hydroxypropanoic acid has two position isomers.

i)
Draw and name the two position isomers of hydroxypropanoic acid.
 
[1]
 
ii)
Identify which isomer is optically active.
 
[1]
3b1 mark

There are 20 amino acids used, by the cells in the human body, for protein synthesis. There is only one amino acid that is not optically active.

Three amino acids are shown in Fig. 3.1.

gly-cys-asp

Fig. 3.1

Identify the amino acid that does not have any effect on plane polarised light.

3c2 marks

Serine, shown in Fig. 3.2, exhibits optical activity.

serineFig. 3.2

Draw three-dimensional representations of the two isomers to show the relationship between them.

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4a1 mark

Benzene can react with aluminium bromide, AlBr3, and bromoethane, CH3CH2Br, to form ethylbenzene.

Write the equation for the formation of the CH3CH2+ species. 

4b1 mark

Name the mechanism for the formation of ethylbenzene from benzene and aluminium bromide.

4c3 marks

Using the CH3CH2+ electrophile, draw the mechanism for the conversion of benzene into ethylbenzene. Include all necessary curly arrows and charges.

4d1 mark

State the type of reaction that occurs in part (c).

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5a3 marks

Compounds KL and M are organic compounds with different properties.

K L M
phenol ethanoyl-chloride 2-phenylpropylamine

 

Give the systematic name of compounds KL and M.

compound K ................................................................................

compound L ................................................................................

compound M ................................................................................

5b2 marks

Complete Table 5.1 to identify if compounds KL and M from part (a) are aliphatic or aromatic.

Table 5.1

  Aliphatic Aromatic
compound K    
compound L    
compound M    
5c4 marks
i)
State what is meant by structural isomerism and give three specific types of structural isomerism.
 
[2]
 
ii)
State what is meant by stereoisomerism and give two specific types of structural isomerism.
 
[2]
5d2 marks

Draw three-dimensional diagrams to show the stereoisomers of compound M.

isomer 1

 

isomer 2

 

optical-isomer-template-1 optical-isomer-template-2

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1a3 marks

Organic compounds can be represented using skeletal formula.

Give the IUPAC names of the compounds A, B and C.

7-1-1a-m-organic-compounds-skeletal-formula

1b2 marks

Compound A can undergo hydrolysis to form a carboxylic acid.

 fwo3gk7j_butanoyl-chloride-and-h2o

Explain why this is an example of an addition-elimination reaction.

1c2 marks

When heated, compound A will also react with phenol in the presence of a base to produce phenyl butanoate.

Draw the displayed formula of phenyl butanoate.

1d2 marks

State whether any of the compounds, A, B or C, can form optical isomers.


Explain your answer.

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2a3 marks

Benzene can exist as C6H6 or be substituted in a number of different ways to form aromatic compounds.

State the IUPAC name for compounds W, X and Y


nrhdxjs-_benzene-compounds
2b1 mark

State the IUPAC name for compound Z.

cd80e300-b21c-42e9-991c-55888972d64d
2c1 mark

State the bond angle that is present in the benzene molecule.

2d1 mark

In benzene, each of the carbon atoms is sp2 hybridised.

i)
Explain how neighbouring carbon atoms form σ bonds.

[1]

ii)
Neighbouring carbon atoms also form π bonds. Explain how these π bonds are formed.

[1]

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3a3 marks

This question is about benzene.

i)
Explain why the benzene molecule is planar.

[2]

ii)
Explain why all of the carbon-carbon bonds in benzene are the same length.

[1]

3b3 marks

Benzene can be nitrated by warming it with a mixture of concentrated sulfuric acid and concentrated nitric acid.

The mechanism for the reaction is shown in Fig. 3.1.

7-1-3b-m-nitration-mechanism
Fig. 3.1


Name the type of mechanism of this nitration reaction. Explain your answer.

3c2 marks

Benzene can be used to synthesise (4-aminophenyl)ethanoic acid which is a drug that can be used to treat chronic inflammation of the intestines.

i)
Draw the structural formula of (4-aminophenyl)ethanoic acid.

[1]

ii)
One of the intermediate products made during the synthesis of (4-aminophenyl)ethanoic acid is the molecule shown in Fig. 3.2.
7-1-3c-m-4-nitromethylbenzene-a

Fig. 3.2

Give the IUPAC name of the molecule shown in Fig. 3.2.

[1]

3d3 marks

Noradrenaline, shown in Fig. 3.3, is a hormone and neurotransmitter which contains a benzene ring. It is released during stress to stimulate the heart and increase blood pressure.

7-1-3d-m-noradrenaline

Fig. 3.3

Other than the arene functional group, state the name of three functional groups in the noradrenaline molecule.

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4a1 mark

Leucine is an optically active amino acid with the molecular formula (CH3)2CHCH2CH(NH2)COOH. 

Draw the displayed formula of leucine.

4b4 marks

Leucine exists as stereoisomers. 

i)

Explain the meaning of the term stereoisomers.

[2]

ii)
Explain how you can distinguish between the isomers.
[2]
4c2 marks

The two optical isomers of leucine taste different. One isomer has a bitter taste, the other is sweet.

Draw the three-dimensional arrangement of the two optical isomers.

4d1 mark

Give the IUPAC name of leucine.

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5a2 marks

Propranolol is an optically active drug that is used to treat hypertension. Its structure is shown in Fig. 5.1.

7-1-5a-m-propranolol-a

Fig. 5.1

i)
Give the molecular formula of propranolol.

[1]

ii)
Circle the chiral centre of propranolol in Fig 5.1.

[1]

5b3 marks

Explain why a racemic mixture of propranolol has no effect on plane polarised light.

5c1 mark

Explain why it is important to separate a racemic mixture of propranolol into pure single enantiomers.

5d1 mark

Chiral catalysts are often used in the manufacturing process of drugs.

i)
What is the purpose of a chiral catalyst?

[1]

ii)
Give one advantage and one disadvantage of using a chiral catalyst.

[2]

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1a3 marks

This question is about aldehydes.

Draw the displayed formula and 3D representations of the smallest aldehyde that can form optical isomers.

displayed formula







optical isomer 1 optical isomer 2









 
 
1b2 marks
i)
Draw the fully displayed formula of the oxidation product of the aldehyde identified in part (a).
 
[1]
 
ii)
State a suitable reagent, including observations, for the oxidation of the aldehyde identified in part (a).
 
[1]
1c2 marks
i)
Write a balanced symbol equation, using structural formulae, to show the reduction of the aldehyde identified in part (a). You should use [H] to show the reducing agent.
 [1]
ii)
State a suitable reducing agent.
 
[1]
1d1 mark

Name the organic compound formed by the reaction of the oxidation product in part (b) and the reduction product in part (c).

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2a2 marks

This question is about the chemistry of limonene.

limonene

Limonene is commonly found in the rinds of citrus fruits such as grapefruit, lemon, lime and oranges. It is a naturally occurring hydrocarbon with the molecular formula C10H16.

Limonene exists as a pair of enantiomers:

  • One enantiomer is responsible for a strong orange smell
  • The other enantiomer is responsible for a lemon smell.

Draw 3D representations of the two enantiomers of limonene.

 
optical isomer 1 optical isomer 2








 

2b3 marks

Suggest why receptors in the human nose can distinguish between the orange and lemon enantiomers of limonene.

2c
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4 marks

Limonene can undergo full hydrogenation to form menthane as shown.

 limonene-hydrogenation

For the complete hydrogenation of an impure sample of 3.00 g of limonene at room temperature and pressure, 870 cm3 of hydrogen was required. 

Calculate the percentage purity of limonene.

(1 mol of hydrogen occupies 24.0 dm3 at room temperature and pressure)

 
 
 

percentage purity = ........................ %

2d2 marks

The final step of the multi-step synthetic conversion of limonene to menthol is shown.

 menthol-synthesis-from-limonene
 

State the reagent for this reaction and the type of reaction.

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3a4 marks

Aldehydes and ketones always react with HCN to form optical isomers.

Discuss this statement, using the general formulae RCHO and R’COR’’. Your answer should include equations where appropriate.

3b3 marks

Acidified K2CrO7 (aq) was heated under reflux with the following β-hydroxyaldehyde shown in Fig. 3.1. 

b-hydroxyaldehyde

Fig. 3.1


Explain the change in chirality, if any, between the β-hydroxyaldehyde and its organic
product.

3c3 marks
Explain the change in chirality, if any, when pent-1-en-3-ol is hydrogenated.
 
3d3 marks

Other isomers of pent-1-en-3-ol, C5H10O, exist.

i)
Draw the displayed formula of the secondary alcohol isomer of pent-1-en-3-ol that exhibits both stereoisomerism and optical isomerism and identify the chiral centre.
 
[2]
 
ii)
Give the IUPAC name for this isomer.
 
[1]

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