Syllabus Edition

First teaching 2020

Last exams 2024

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Nitrogen Compounds (CIE AS Chemistry)

Exam Questions

2 hours31 questions
1a2 marks

Propylamine can be produced from 1-bromopropane.

Complete the equation for the formation of propylamine.

CH3CH2CH2Br + .................................  →  .................................  + HBr

1b3 marks

State the necessary reagents and conditions to produce propylamine from 1-bromopropane.

1c1 mark

Name the reaction mechanism that takes place when propylamine is produced from 1-bromopropane.

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2a2 marks

When 1-chloropropane is heated under reflux with ethanolic potassium cyanide, KCN, the following reaction occurs.

CH3CH2CH2Cl + KCN → CH3CH2CH2CN + KCl

i)
Draw the displayed formula of the organic product formed in this reaction.

[1]

ii)
State the IUPAC name of this organic product.

[1]

2b1 mark

Suggest why this reaction is useful to chemists during the synthesis of other organic compounds.

2c3 marks

The CH3CH2CH2CN can undergo hydrolysis.

i)
Write the equation for the acid hydrolysis of CH3CH2CH2CN.

[2]

ii)
Draw the displayed formula of the intermediate formed when CH3CH2CH2CN is hydrolysed by sodium hydroxide.

[1]

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3a1 mark

This question is about hydroxynitriles.

The hydroxynitrile shown in Fig. 3.1 can be prepared from the reaction between propanal and hydrogen cynaide.

3-7-3a-e-2-hydroxybutanenitrile

Fig. 3.1

Give the IUPAC name of this hydroxynitrile.

3b4 marks

Using 'curly arrows', complete the reaction mechanism shown in Fig. 3.2 for the reaction between propanal and the cyanide ion, CN.

Include any lone pairs of electrons and partial or whole charges.

3-7-3b-e-propanal-and-cn--mechanism-a

Fig. 3.2

3c1 mark

Name the type of reaction mechanism shown in Fig. 3.2.

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1a2 marks

Propylamine is a colourless liquid that is used to manufacture a variety of chemicals including textile resins, drugs and pesticides. It can be produced by the reaction of 1-chloropropane with ammonia.

3-7-4a-m-chloropropane-and-nh3-to-propylamine

i)
State the role of the ammonia in this reaction.
 
[1]
 
ii)
Name the type of reaction that occurs in this synthesis of propylamine.
 
[1]
1b3 marks

Use an appropriate chemical equation to explain why propylamine can be described as a Brønsted-Lowry base with water.

1c3 marks

The reaction between 1-chloropropane and ammonia proceeds in two steps.

 

Step 1 involves the formation of an intermediate.

Step 2 forms the final propylamine product.

 

As the reaction proceeds, the bond angles around the nitrogen atom change. Explain these changes in the bond angles around the nitrogen atom.

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2a5 marks

Fig. 1.1 shows a reaction sequence to form an amine.

3-7-2a-m-butylamine-reaction-scheme

Fig. 1.1

i)
Name compound A.
 
[1]
 
ii)
Reaction 1 heats compound A under reflux with an ethanolic solution of potassium cyanide.
 
Draw the mechanism for the reaction of compound A with the ethanolic solution of potassium cyanide to form compound B.
 
  • Identify the ion that reacts with compound A
  • Draw the product of this reaction, compound B.
  • Include all charges, partial charges, lone pairs and curly arrows.
[4]
2b1 mark

In reaction 2, vapours of compound B are converted into compound C by reacting them with hydrogen gas over a nickel catalyst.

 

Name the type of reaction that occurs in reaction 2

2c3 marks

Compound C can also be produced in a single step from compound D.

 
i)
Draw the displayed formula of compound D.
 
[1]
 
ii)
State suitable reagents and conditions for reaction 3.
 
[2]
2d2 marks

Compound C is a primary amine as there is one alkyl chain attached to the nitrogen atom.

 

Draw the skeletal formula of compound C's two isomers, which are also primary amines.

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3a2 marks

Propanal undergoes nucleophilic addition with a mixture of HCN and NaCN to make 2-hydroxybutanenitrile, CH3CH2CH(OH)CN.

The mechanism for this reaction occurs in two main steps. The first step involves a nucleophile attacking the carbonyl carbon of propanal.

 

Explain which species acts as the nucleophile during this reaction. 

3b3 marks

The second step in the mechanism involves an intermediate species, CH3CH2C(O)HCN, reacting with HCN to form 2-hydroxybutanenitrile.

 

Draw the mechanism for this step.

  • Identify the intermediate species that reacts with HCN.
  • Include all charges, partial charges, lone pairs and curly arrows. 
3c2 marks

The structure of the 2-hydroxybutanenitrile product is shown in Fig. 1.1.

 
2-hydroxybutanenitrile-bond-angles
 
Fig. 1.1
 

Predict the values for the bond angles a and b shown in the diagram.

3d4 marks

The product 2-hydroxybutanenitrile exists as a pair of stereoisomers.

 
i)
Name the type of stereoisomerism shown by 2-hydroxybutanenitrile.
 
[1]
 
ii)
Draw three-dimensional diagrams of this pair of stereoisomers. Indicate with an asterisk (*) the chiral centre on one of the structures drawn.
 
[3]

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4a4 marks

Two students try to prepare butanoic acid from a halogenoalkane in the laboratory.

Both students perform a nucleophilic substitution reaction to form P in reaction 1 of Fig. 1.1.

They both form butanoic acid from P but student A uses a single reaction, while student B uses two reactions.

3-7-4a-m-halogenoalkane-to-butanoic-acid

Fig. 1.1

i)
State the reagents and conditions required for reaction 1.
 
[2]
 
ii)
Student A uses 1-bromopropane to form P.
 
Student B uses a different halogenoalkane which forms P at a slower rate.
 
Suggest the identity of the halogenoalkane that student B uses. Explain your answer.
 
[2]
4b2 marks

Student A converts into butanoic acid in a single step, reaction 2.

 
i)
Name the type of reaction occurring in reaction 2.
 
[1]
 
ii)
State an appropriate reagent for reaction 2 and name the other product of the reaction.
 
[1]
4c1 mark

Student B converts P into Q using dilute sodium hydroxide in reaction 3. This is followed by acidification of the product in reaction 4 to form butanoic acid.

 

Draw the structural formula of Q.

4d2 marks

Explain why it is likely that student A will have a higher overall yield of butanoic acid from their halogenoalkane than student B.

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5a6 marks

Halogenoalkanes are often used as intermediates in organic reactions.

Three reactions of bromoethane, CH3CH2Br, are shown if Fig. 1.1.

3-7-5a-m-bromoethane-reactions

Fig. 1.1

For each reaction, state the reagent and solvent used.

 

reaction 1

reagent ............................................................

solvent ............................................................

reaction 2

reagent ............................................................

solvent ............................................................

reaction 3

reagent ............................................................

solvent ............................................................

5b4 marks

Reactions 1 and 3 require specific reaction conditions to occur as shown in Fig. 1.1.

 

For each reaction, give another solvent and the alternative product that will be formed.

reaction 1

alternative solvent ............................................................

alternative product ............................................................

reaction 3


alternative solvent ............................................................

alternative product ............................................................

5c2 marks

The product of reaction 2 can be converted into CH3CN.

 
i)
Name the compound CH3CN.
 
[1]
 
ii)
Name the type of reaction used to form CH3CN.
 
[1]
5d5 marks

The product of reaction 3 can be used to produce propanoic acid by two different hydrolysis reactions.

 

Compare the two types of hydrolysis reaction in the production of propanoic acid from the product of reaction 3.

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1a3 marks

Compound X is produced from cyclohexene. An amine which is a relatively weak base containing one nitrogen atom can be produced from compound X in one step. 

Outline a mechanism for the formation of compound X from cyclohexene. You will need to give suitable reagents in your answer. 

1b2 marks

One condition that is needed to convert compound X into the amine molecule is that the reagent needs to be in excess.

ii)
State the reagent and any other required conditions for the reaction.
[2]
ii)
Suggest why the reagent needs to be in excess.

[1]

1c1 mark

Propylamine acts as a Brønsted-Lowry base when it reacts with water.

Suggest an equation to show how propylamine reacts when mixed with water.

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2a2 marks

2-hydroxy-2-phenylpropanenitrile is shown in Fig. 2.1.

3-7-2a-h-2-hydroxy-2-phenylpropanenitrile-a

Fig. 2.1

Deduce the number of sigma (σ) and pi (π) bonds in 2-hydroxy-2-phenylpropanenitrile.

 
sigma ..............................
 
pi ..............................

2b3 marks

A molecule of 2-hydroxy-2-phenylpropanenitrile contains sp, sp2 and sp3 hybridised carbon atoms.

 

State the number of sp, sp2 and sp3 hybridised carbon atoms in a molecule of 2-hydroxy-2-phenylpropanenitrile.

2c4 marks

2-hydroxy-2-phenylpropanenitrile can be produced from compound X, a secondary alcohol, in a two-step synthesis.

compound X rightwards arrow with step space 1 on top compound Y rightwards arrow with step space 2 on top 2-hydroxy-2-phenylpropanenitrile-2

State the reagents and conditions required for step 1 and step 2.

reagents for step 1 ......................................................................
conditions for step 1 ......................................................................
reagents for step 2 ......................................................................
conditions for step 2 ......................................................................

2d7 marks
i)
Draw the mechanism for the second step in the synthesis of 2-hydroxy-2-phenylpropanenitrile.

You should clearly show the structure of compound Y and any intermediate formed and include all relevant charges, partial charges, curly arrows and lone pairs.

[6]

ii)
Draw the structure of compound X.
[1]

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3a1 mark

2,2-dimethylpentanenitrile is useful in the synthesis of a variety of medicines and pharmaceuticals. 

Draw the skeletal formula of 2,2-dimethylpentanenitrile.

3b2 marks

2,2-dimethylpentanenitrile undergoes hydrolysis when heated with dilute hydrochloric acid.

Write an equation for the hydrolysis of 2,2-dimethylpentanenitrile.

3c3 marks

2,2-dimethylpentanoic acid can also be produced by the hydrolysis of 2,2-dimethylpentanenitrile using sodium hydroxide but this occurs in two steps.

i)
Draw the fully displayed formula of the intermediate organic product.

[1]

ii)
State the other product formed with this intermediate organic product.

[1]

iii)
State the type of reaction that is required to produce 2,2-dimethylpentanoic acid from this intermediate organic product.

[1]

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