Amines (A Level only) (AQA A Level Chemistry)

Exam Questions

3 hours30 questions
1a3 marks

State whether the following amines can be classed either primary, secondary or tertiary.

i)
Ethylamine

ii)
2-aminopropane

iii)
Phenylamine 
1b3 marks

Name the amines shown in Figure 1.

Figure 1

1-9

1c2 marks

Complete the equation for the formation of ethylamine.

CH3CH2Br + __________ → __________ + NH4Br

1d3 marks

State the reagents and conditions required for the conversion of 1-bromopropane into propylamine.

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2a4 marks

Chloroethane will react with ethylamine to produce a secondary amine. Complete the reaction mechanism in Figure 1 for the formation of the secondary amine. 

Figure 1

2-8

2b1 mark

Give the name of the mechanism outlined in part (a) 

2c1 mark

Chloroethane, CH3CH2Cl, can also produce an amine by first heating under reflux with ethanolic potassium cyanide, KCN. The amine can then be formed in the second step from the nitrile produced.

State the conditions required to produce the amine in the second step of this method.

2d1 mark

State one disadvantage for the preparation of an amine from a halogenoalkane in one step as opposed to a two step process. 

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3a2 marks

Write an equation to show how propylamine can act as a base if reacted with hydrochloric acid and give the name of the product formed. 

3b3 marks

Explain why phenylamine, shown in Figure 1,  is a weaker base than ammonia. 

Figure 1

3-8

3c3 marks

Explain why ammonia is a weaker base than methylamine.

3d1 mark

Phenylamine can be prepared from nitrobenzene, state the reagents and conditions required for this reaction. 

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4a1 mark

Quaternary ammonium salts can be made from the reaction of a halogenoalkane such as chloroethane with ammonia. Give a use of a quaternary ammonium salt.

4b1 mark

State the name of the quaternary ammonium salt shown in Figure 1.

Figure 1

4-8

4c1 mark

Give a condition for the reaction between chloroethane and ammonia that would favour the formation of a quaternary ammonium salt. 

4d3 marks

Outline the reaction mechanism between a molecule of chloroethane and two molecules of ammonia to produce ethylamine.

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5a3 marks

Explain why secondary amines are stronger bases than primary amines.

5b5 marks

Complete the nucleophilic addition elimination mechanism outlined in Figure 1 to show the formation of an amide from ethanoyl chloride and ammonia and state the name of the final product.

Figure 1

5-5

5c1 mark

Another amide is produced in a separate reaction, this is shown in Figure 2. State the name of this amide.

Figure 2

6-6

5d3 marks

Give two disadvantages of using an acid chloride to produce an amide and give an alternative reagent to form an amide from an amine.

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1a2 marks

Name the compound drawn in Figure 1 and state the class of compound to which it belongs.

Figure 1

1-10

1b5 marks

The compound in Figure 1 in part (a) can be formed during the reaction of ethylamine, CH3CH2NH2, and chloroethane, CH3CH2Cl.

Name and outline the mechanism for this reaction.

1c1 mark

Explain why an excess of ethylamine, CH3CH2NH2, is required for the formation of the compound in Figure 1 in part (a).

1d4 marks

Triethylamine, (CH3CH2)3N and the compound in Figure 1 of part (a) are two different types of amines.

i)
Explain how you could differentiate between these two compounds using an IR spectrum.

ii)
Triethylamine, (CH3CH2)3N can also undergo a reaction with chloroethane. Draw and give a use for the product of this reaction.

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2a7 marks

Three nitrogen containing molecules, ammonia, NH3, phenylamine, C6H5NH2 and N-methylethylamine, CH3CH2NHCH3, are drawn below respectively in Figure 1.

Figure 1

2-9

 

i)
List the three amine molecules drawn in Figure 1 in order of increasing base strength.

ii)
Explain your answer to part (b) (i).
2b3 marks

Phenylamine, C6H5NH2 shown in Figure 1 in part (a) can be produced from nitrobenzene, C6H5NO2.

Name the type of reaction and suggest suitable reagents and conditions for this conversion.  

2c3 marks

Azo dyes are organic compounds, which are largely used in the treatment of textiles andleather products, as well as in food. Phenylamine, C6H5NH2, can be used in the manufacture of azo dyes.

The manufacturing process is outlined below.

Step 1

Phenylamine is dissolved in HCl to produce a diazonium salt. A diazonium salt contains two nitrogen atoms joined together by a triple bond. The reaction for this process is as follows:

C6H5NH2  +  HCl   +  HNO2   →    C6H5N2+Cl-    +   2H2O

Step 2

This solution is then slowly added to an alkaline solution of a phenol coupling agent to form the dye.

i)
The diazonium salt, C6H5N2+Cl-, is an unstable compound. Suggest a condition that could be added to ensure that the salt would not break down during the reaction.

 

ii)
Draw the structure of the diazonium salt formed in Step 1, showing the displayed formula of the nitrogen containing group.

 

2d2 marks

Phenol, C6H5OH, is an aromatic organic compound which is also crucial in the manufacture of azo dyes.

The final step of the azo dye production, involves pairing up the diazonium salt with a phenol compound as a coupling agent.

Suggest a structure for the azo dye if the coupling agent used is 2,6-dimethylphenol.

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3a6 marks

Amines will react with acid chlorides to produce a different nitrogen containing product. 

i)
Name and outline the mechanism between ethanoyl chloride, CH3COCl and methylamine, CH3NH2.

ii)
Give the IUPAC name of the compound formed in the reaction.
3b4 marks

Name and draw the structure of the two compounds formed in the reaction of methylamine, CH3NH2 and propanoic anhydride.

3c2 marks

Methylamine, CH3NH2 also reacts with ethanoic anhydride, CH3COOCOCH3 in a less vigorous reaction. Suggest why using an acid anhydride such as ethanoic anhydride is more favourable than using ethanoyl chloride.

3d4 marks
i)
Two separate solutions of methylamine, CH3NH2 and dimethylamine, (CH3)2NH, were left unlabelled in a laboratory. Suggest how, other than smell, they could be distinguished from one another.

ii)
Give an explanation to your answer to part (i).

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4a4 marks

Figure 1 shows a reaction scheme in which Compound A undergoes three different reactions to produce three different products. 

Figure 1

8-4

Explain how the reactions and the conditions of Reaction 2 and Reaction 3 are different from one another.

4b6 marks

Compound B drawn in Figure 1 of part (a) is a primary amine. 

Give the IUPAC name of Compound B and outline a mechanism for Reaction 1, stating a condition which would reduce contamination of the primary amine.

4c1 mark

Draw a branched chain optical isomer of Compound B from Figure 1 that would display optical isomerism.

4d7 marks

An alternative method of producing Compound B in Figure 1 part (a) is from 1-bromopropane, CH3CH2CH2Br in two steps.

i)
State the reagents and conditions required for both steps of this reaction and give the name of the intermediate compound formed.

ii)
Suggest one advantage and one disadvantage for this method.

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5a3 marks

The compound drawn in Figure 1 below is caffeine. Caffeine is a stimulant drug that speeds up the messages travelling between the brain and body.
Ingesting too much caffeine may promote headaches and high blood pressure.

Figure 1
12-1

i)
Give the molecular formula of caffeine.

ii)
Calculate the percentage by mass of nitrogen in caffeine. Give your answer to 1 decimal
5b1 mark

Deduce the total number of peaks in the 13C NMR spectrum of caffeine.

5c2 marks
i)
Which functional group is not present in a molecule of caffeine drawn in Figure 1 part (a)?

A         Alkene 

B         Ketone 

C         Amine 

D         Amide

ii)
Give the name, including the classification, of the functional group that contains the Nitrogen atom labelled c.
5d3 marks

Suggest why the nitrogen atoms labelled a and b are unlikely to be protonated. 

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1a2 marks

Compounds A, B, C and D shown in Figure 1 are all nitrogen compounds.

State the IUPAC names for compounds A and B.

Figure 1

1-11

 

1b3 marks

State which amine is more basic, compound C or D. Explain your answer.

1c2 marks

Explain why 2-chloropyridine shown in Figure 2 is less basic than pyridine.

Figure 2

2-10

1d5 marks

Outline the mechanism for the formation of compound B using the required acyl chloride. 

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2a3 marks

Phenylamine is a weak base and can be prepared from benzene in two steps. State the reagents and conditions required for the preparation of phenylamine from benzene.

2b1 mark

Write an equation to show how the free amine is liberated from the salt formed in the second step using sodium hydroxide. 

2c4 marks

Explain why phenylamine can not be prepared from chlorobenzene via reaction with ammonia under normal conditions.

2d2 marks

Explain why phenylamine is insoluble in water.

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3a3 marks

2-bromopropane can undergo a two step process to form a primary amine containing four carbon atoms.

i)
State the name of the primary amine produced after both steps.

ii)
Give the reagents and conditions required to form the intermediate compound in step one.
3b3 marks

In step two the amine is produced from the intermediate formed in step 1.

i)
Draw the structure for the intermediate formed in step one.

ii)
State the reagents and conditions required for step two.

iii)
Write an equation for the reaction that occurs in step two. 
3c4 marks

If excess 2-bromopropane is used in part (a), further substitution will occur. Outline the mechanism for the formation of the tertiary amine from a secondary amine for the reaction between excess 2-bromopropane and propylamine. 

3d1 mark

A solid product is produced in the reaction in part (c). Draw the structure of the solid produced in this reaction.

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4a3 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.

4b2 marks

State the reagents and conditions for the conversion of Compound X into the amine molecule. 

4c5 marks

Figure 1 shows three amine compounds, Compounds E, F and G.

Figure 1

3-10

i)
Rank the following amines in increasing order of basicity.

ii)
Explain your answer to part (i).

4d1 mark

Write an equation to show how propylamine will react when mixed with water.

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5a1 mark

Methyl orange is an azo dye which exists in two forms depending on the pH. 

Figure 1

4-10

Suggest a structure for the diazonium salt that is used to form methyl orange which has the formula C6H4(SO3Na)NH2.

5b2 marks

Ethylamine will react with propanoic anhydride to produce two compounds, draw the compounds produced in this reaction. 

5c3 marks

A reaction scheme for the production of a secondary amine, Compound Z, is given in the following sequence shown in Figure 2.

Figure 2
5-7

i)
Give the reagents and conditions required for Step 1.

ii)
Give the IUPAC name for compound Y.
5d3 marks

The amine produced, compound Z, is a secondary amine.

i)
Propylamine is reacted with chloromethane to produce compound Z. Draw a possible structure for compound Z.

ii)
Give one advantage of forming an amine through this method.

iii)
Compound Z is reacted with excess chloromethane. Draw the solid product formed from this reaction.

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