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Edexcel International A Level Chemistry

Reactions of Alkenes

Alkenes react because the C=C double bond contains an exposed pi bond with high electron density. These pages separate the key alkene reactions so that students can revise the reagent, conditions, observations and products for each pathway.

Exam Unit
Unit 1
WCH11/01 – IAS
Specification Points
5.4 – 5.6
3 points covered
Sub-topics
6 lessons
Revision notes available
Exam Board
Edexcel IAL
Pearson International

Revision Notes

6 revision notes, in the order the specification teaches them.

A halogen molecule approaching a carbon-carbon double bond
1

Halogens

Revise addition of halogens to alkenes and how dihalogenoalkanes form across the carbon-carbon double bond.

Start revising
A hydrogen halide molecule approaching a carbon-carbon double bond
2

Hydrogen Halide

Learn how hydrogen halides add to alkenes to form halogenoalkanes, including the importance of the C=C bond.

Start revising
An orange test tube beside a colourless one, the bromine water test
3

Bromine Water

Revise the chemical test for alkenes, including the colour change when bromine water reacts with a C=C bond.

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A double bond and a hydrogen molecule on a metal catalyst surface
4

Hydrogen

Learn how hydrogenation converts alkenes into alkanes by adding hydrogen across the double bond.

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A steam cloud and water molecule beside a double bond
5

Steam

Revise hydration of alkenes and how steam is used to produce alcohols under suitable conditions.

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A purple test tube beside a colourless one, the manganate test
6

KMnO₄

Review oxidation of alkenes with potassium manganate(VII), including the key reagent and expected test observations.

Start revising

Summary Map

Download, print and revise the reactions of this topic at a glance.

Summary map

Download, print and revise the reactions of this topic at a glance.

Illustration of a summary map: compounds joined by reaction arrows
Summary map · PDF

Alkenes Map

Edexcel International A Level Chemistry · Unit 1 · Topic 5

Every reaction on one A4 page: reagents, conditions and reaction type for each arrow, colour coded, with the key tests.

Download the map6 reactions · A4 portrait · print ready

© 2026 Online Learning System. For personal study: printing is allowed; editing, copying and redistribution are not.

Virtual Lessons

Recorded video lessons that teach the topic step by step.

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Virtual Lessons

Taught step by step in 4 recorded video lessons, to watch at your own pace.

Topic 5 Alkenes taught by a specialist chemistry teacher, in 4 recorded video lessons that follow the specification.

  • Learn it before you revise itEach lesson explains the chemistry step by step, with the diagrams, mechanisms and worked examples the exam expects.
  • At your own pacePause, rewind and rewatch any part. Each lesson opens where you stopped.
  • Your progress is keptA lesson is ticked off once you have watched most of it, here and in your course on Moodle.

MCQ Bank

Multiple-choice papers on this topic, marked the moment you submit. MCQ (A) is free.

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Test yourself: 5 MCQ papers

Exam-style multiple-choice papers, marked the moment you submit with every answer explained. MCQ (A) is free.

5 exam-style multiple-choice papers, MCQ (A) to (E): 90 questions on Topic 5 Alkenes, written the way the exam asks them.

  • Marked the moment you submitYour score straight away, with every answer explained, right or wrong.
  • Revise what you missedEach explanation links to the revision notes for that point.
  • MCQ (A) is freeTry the first paper now. MCQ (B) to (E) come with the course.
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SAQ Bank

Written, drawn and worked exam practice on this topic, marked by a specialist chemistry teacher.

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Written and drawn answers: 12 papers

Draw, write and calculate the way the exam asks, then a specialist chemistry teacher marks your work.

12 exam papers, (A) to (L): 170 questions on Topic 5 Alkenes with no multiple choice. You write explanations, work out calculations and draw answers: structures, mechanisms and diagrams.

  • Answer the way the exam asksThe real paper wants written, worked and drawn answers, so that is how you practise.
  • Marked by a teacher, assisted by KASPA specialist chemistry teacher marks every answer against the mark scheme, with feedback on what to fix.
  • One paper marked each weekYour marked paper comes back here with every marking point shown.
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Revision Game

Match reagents to products, free, with your board's reagents and conditions.

Illustration of memory game cards, two turned face up as a matching pairFree

Revision Game: Alkenes

Turn the cards over two at a time: match reagents to what they make, and find how each product is made.

A free memory game on the reactions in this topic, with your board's reagents, conditions and spec points.

  • Two ways to playMatch each set of reagents to what the reaction makes, or see a product and find the reactant and reagents that make it.
  • Drawn the way the exam draws themEvery structure is drawn in ChemDraw, with the reagents and conditions your exam board asks for.
  • It countsRounds earn XP and keep your streak going, and every correct match shows in your KASP analytics, apart from your marks.

Study Cards

Pick a deck, then turn each card to check what you remember.

Specification

Every specification point in this topic, in the exam board's own words. Rate how confident you are with each one.

Official Pearson Edexcel IAL documentsSpecification (opens the Pearson Edexcel IAL website in a new tab)Data booklet (opens the Pearson Edexcel IAL website in a new tab)

Self-assessment · 26 points

Sign in to rate how confident you feel about each point. Your ratings are saved to your account, follow you to any device, and appear beside your KASP analytics, kept apart from your marks.

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5.1

  1. a

    know the general formula of alkenes

    Revise
  2. b

    understand that alkenes are unsaturated hydrocarbons

    Revise
  3. c

    understand that cycloalkenes are unsaturated hydrocarbons

  4. d

    understand that a carbon-carbon double bond consists of a sigma bond

    Revise
  5. e

    understand that a carbon-carbon double bond consists of a pi bond

    Revise

5.2

  1. a

    be able to explain geometric isomerism in terms of restricted rotation around a C=C double bond

    Revise
  2. b

    be able to explain geometric isomerism in terms of the nature of the substituents on the carbon atoms

    Revise

5.3

  1. a

    understand the E-Z naming system for geometric isomers

    Revise
  2. b

    understand why the E-Z naming system is necessary when the cis-trans naming system breaks down

    Revise

5.4

  1. i

    be able to describe the reactions of alkenes, limited to: the addition of hydrogen, using a nickel catalyst, to form an alkane

    Revise
  2. ii

    be able to describe the reactions of alkenes, limited to: the addition of halogens to produce a di-substituted halogenoalkane

    Revise
  3. iii

    be able to describe the reactions of alkenes, limited to: the addition of hydrogen halides to produce mono-substituted halogenoalkanes

    Revise
  4. iv

    be able to describe the reactions of alkenes, limited to: the addition of steam, in the presence of an acid catalyst, to produce alcohols

    Revise
  5. v

    be able to describe the reactions of alkenes, limited to: oxidation of the double bond by acidified potassium manganate(VII) to produce a diol

    Revise

5.5

  1. a

    know the qualitative test for a C=C double bond using bromine

    Revise
  2. b

    know the qualitative test for a C=C double bond using bromine water

    Revise

5.6

  1. i a

    be able to describe the electrophilic addition mechanism of bromine to ethene, including diagrams and evidence where possible

    Revise
  2. i b

    be able to describe the electrophilic addition mechanism of hydrogen bromide to ethene, including diagrams and evidence where possible

    Revise
  3. ii a

    be able to describe the electrophilic addition mechanism of hydrogen bromide to propene, including diagrams and evidence where possible

    Revise
  4. ii b

    use curly arrow notation in electrophilic addition mechanisms, with curly arrows starting from a bond or lone pair of electrons

    Revise
  5. ii c

    know the relative stability of primary, secondary and tertiary carbocation intermediates

    Revise

5.7

  1. a

    be able to describe addition polymerisation of alkenes

    Revise
  2. b

    be able to draw the repeat unit of an addition polymer given the monomer

    Revise
  3. c

    be able to draw the monomer given the repeat unit of an addition polymer

    Revise

5.8

  1. i

    understand how chemists limit the problems caused by polymer disposal by: developing biodegradable polymers

    Revise
  2. ii

    understand how chemists limit the problems caused by polymer disposal by: removing toxic waste gases produced by the incineration of polymers

    Revise