Reactions of Alkenes
Use this landing page to move quickly between the main alkene reaction revision pages for OCR A Level Chemistry A section 4.1.3. These pages cover addition reactions with halogens, hydrogen halides, bromine water, hydrogen and steam.
Choose a Reactions of Alkenes Page
Alkenes react because the carbon-carbon double bond contains an electron-rich pi bond. These pages separate the key addition reactions and chemical tests so students can revise reagents, conditions, products and observations clearly.
Key idea: Most alkene reactions are addition reactions. The pi bond breaks, two new sigma bonds form and the atoms from the reagent add across the C=C double bond.
Halogens
Revise the addition reactions of alkenes with halogens, including how the C=C bond reacts with Br₂ and Cl₂.
Start revisingHydrogen Halide
Learn how hydrogen halides add across the C=C bond and how major products can form with unsymmetrical alkenes.
Start revisingBromine Water
Review the bromine water test for unsaturation, including the colour change from orange to colourless.
Start revisingHydrogen
Revise hydrogenation of alkenes, including conversion to alkanes using a nickel catalyst.
Start revisingSteam
Learn how steam adds to alkenes in hydration reactions to produce alcohols under suitable conditions.
Start revisingHow to Use These Pages
Start with halogen and hydrogen halide addition to secure the core electrophilic addition pattern. Then revise bromine water as the test for unsaturation, followed by hydrogenation, hydration with steam.
Exam focus: Be able to state reagents and conditions, predict products from alkene addition reactions, describe the bromine water colour change.
Master Alkenes for OCR A Level Chemistry A
Continue from these free revision notes into the full 4.1.3 Alkenes course. The guided video lessons are ready now; the OCR A MCQ bank, teacher-marked short-answer questions and KASP spec-point report are being written, and the course opens for enrolment as soon as they are complete.
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Some ionic radii are shown.
| Ion | Ionic radius / nm |
|---|---|
| Na+ | 0.102 |
| K+ | 0.138 |
| F− | 0.133 |
| Cl− | 0.180 |
Which compound has the strongest ionic bonding?
Explain why the metallic bonding in magnesium is much stronger than that in sodium.
Copyright notice: This revision page, including its written explanations, layout and teaching sequence, is produced for Online Learning System by Dr. Mohammed Al-Fatah. It is intended for student revision and may not be copied, redistributed or republished without permission.
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