For Examiners Use - Materials For this paper you must have: • the...

*Jun25 7404201* IB/M/Jun25/G4002/V7 7404/2

For Examiner’s Use Question Mark 1 2 3 4 5 6 7 Section B TOTAL

Tuesday 20 May 2025 Morning Time allowed: 1 hour 30 minutes

Materials

For this paper you must have:

• the Periodic Table/Data Sheet, provided as an insert (enclosed) • a ruler with millimetre measurements • a scientific calculator, which you are expected to use where appropriate.

Instructions • Use black ink or black ball-point pen.• Fill in the boxes at the top of this page.• Answer all questions.• You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages.• If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s).• All working must be shown.• Do all rough work in this book. Cross through any work you do not want to be marked.

Information • The marks for questions are shown in brackets.• The maximum mark for this paper is 80.

Advice • You are advised to spend 65 minutes on Section A and 25 minutes on Section B.Please write clearly in block capitals.Centre number

Candidate number

Surname

Forename(s)

Candidate signature

I declare this is my own work.

AS

CHEMISTRY

Paper 2 Organic and Physical Chemistry 1 / 4

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IB/M/Jun25/7404/2

Do not write outside the box Section A

Answer all questions in this section.

• 1

This question is about halogenoalkanes.

• 1

. 1 Halogenoalkanes undergo substitution reactions with nucleophiles such as CN – , NH3 and OH –

Explain why halogenoalkanes react with nucleophiles.[2 marks]

• 1

. 2 2-Bromobutane reacts with ammonia to form CH3CH(NH2)CH2CH3

Complete the mechanism for this reaction.[3 marks]

2-Bromobutane reacts with KOH to give a mixture of products.

• 1

. 3 Identify the solvent that should be used to ensure that butan-2-ol is the main organic product when 2-brombutane reacts with KOH [1 mark]

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3

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IB/M/Jun25/7404/2

Do not write outside the box

• 1

. 4 Under different conditions, 2-bromobutane reacts with KOH to form but-1-ene and two other alkenes.

Name and complete the mechanism to form but-1-ene from 2-bromobutane.

Identify the other two alkenes formed.[5 marks]

Name of mechanism

Mechanism

Other alkene 1

Other alkene 2

• 1

. 5 The carbocation (CH3)3C + is formed as an intermediate in the reaction of 2-bromo-2-methylpropane with KCN

Suggest the value of the bond angle around the central C atom in the

(CH3)3C

+ carbocation.[1 mark]

Question 1 continues on the next page

• / 4

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*04* IB/M/Jun25/7404/2

Do not write outside the box

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• 1

. 6 A co-ordinate bond is formed when the (CH3)3C + carbocation reacts with CN – to form a nitrile.

Explain how this co-ordinate bond is formed during this reaction.[2 marks]

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