Organic Chemistry: Halogenoalkanes (Edexcel International A Level Chemistry)

Exam Questions

1a1 mark

1-bromopropane is used for spot removal when ‘dry cleaning’ clothes.

1-bromopropane does not occur naturally but can be made from propan-1-ol.
Identify the reagent or reagents you would use to make 1-bromopropane from propan-1-ol.

1b8 marks

Some reactions of 1-bromopropane are shown.

q18b-paper-2-june-2021-edexcel-ial-chemistry
i)
Give the conditions for the formation of propene.

(1)

ii)

Give the molecular formula of product B.

(1)

iii)

Name the type and mechanism of the reaction taking place in reaction C.

(2)

iv)
Complete the mechanism for the reaction that occurs between ammonia and 1-bromopropane to form propylamine, CH3CH2CH2NH2 .
Include curly arrows, and relevant lone pairs and dipoles.

(4)

q18b-iv-paper-2-june-2021-edexcel-ial-chemistry

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2a2 marks

Ammonia reacts with 1‐chlorobutane.

State the type and mechanism of this reaction.

2b5 marks

A student drew the first step of the mechanism for the reaction.

q20b-paper-2-jan-2022-edexcel-ial-chemistry
i)
Identify two omissions in the student’s mechanism.

(2)

ii)
To obtain butylamine, sodium hydroxide solution is added.
Complete the next step of the mechanism to form butylamine, showing curly arrows, relevant lone pairs and the reaction products.

(3)

q20b-ii-paper-2-jan-2022-edexcel-ial-chemistry

2c3 marks

The reactions of ammonia and of hydroxide ions with halogenoalkanes are similar.

Compare the rate of reaction of ammonia with 1‐chlorobutane and with 2‐bromo‐2‐methylpropane.
Justify your answer.

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3a3 marks

This question is about halogenoalkanes.

The rates of hydrolysis of 1-chloropropane, 1-bromopropane and 1-iodopropane in reactions with aqueous silver nitrate solution were compared.

i)

State what would be measured in the experiment to compare the rates of hydrolysis.

(1)

ii)

State which of these halogenoalkanes would hydrolyse the fastest.
Justify your answer.

(2)

3b2 marks

The equation for the hydrolysis of 1-chloropropane by aqueous hydroxide ions is shown.

CH3CH2CH2Cl + OH → CH3CH2CH2OH + Cl

Give the mechanism for this hydrolysis.
Include curly arrows, and relevant dipoles and lone pairs.

3c4 marks

The boiling temperatures of some halogenoalkanes are shown.

Halogenoalkane Boiling temperature / °C
1-chloropropane 47
1-bromopropane 71
1-iodopropane 103


Explain the trend in boiling temperature of these halogenoalkanes by comparing the intermolecular forces involved.

Detailed explanations of the forces involved are not required.

3d3 marks

In another experiment, 2-bromobutane is heated with ethanolic potassium hydroxide and an elimination reaction occurs.

Draw the skeletal formulae of the three possible organic products, giving their names.

Skeletal formula Name
   
   
   

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4a6 marks

The compound DMAA was originally synthesised as a decongestant.

q20-paper-2-jan-2021-edexcel-ial-chemistry

A suggested synthetic route for DMAA is shown.

q20-1-paper-2-jan-2021-edexcel-ial-chemistry

i)
Give the systematic name of compound A.

(1)

ii)
 Identify, by name or formula, a suitable reagent for Step 1.

(1)

iii)

Give the mechanism for the reaction in Step 2.

Include curly arrows, and any relevant dipoles and lone pairs.

(4)

4b6 marks

DMAA is only slightly soluble in water but dissolves readily in hydrochloric acid to form an aqueous solution.

q20b-paper-2-jan-2021-edexcel-ial-chemistry
i)
Explain the type of bonding that occurs between the nitrogen atom and the hydrogen ion, when the positive ion forms.

(3)

ii)
Complete the diagrams to show how the ions formed in the reaction between DMAA and hydrochloric acid interact with water molecules.

(3)

q20b-ii-paper-2-jan-2021-edexcel-ial-chemistry

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