This deep dive covers Addition Reactions of Alkenes within Alkenes for GCSE Chemistry. Revise Alkenes in Organic Chemistry for GCSE Chemistry with 20 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 6 of 14 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 6 of 14
Practice
20 questions
Recall
15 flashcards
⚗️ Addition Reactions of Alkenes
Alkenes undergo addition reactions — atoms ADD ACROSS the double bond, breaking it and forming two single bonds.
1. Addition of Hydrogen (Hydrogenation)
Ethene + Hydrogen → Ethane
C₂H₄ + H₂ → C₂H₆
Conditions: Ni catalyst, 150°C
C₂H₄ + H₂ → C₂H₆
Conditions: Ni catalyst, 150°C
2. Addition of Bromine (Bromination)
Ethene + Bromine → 1,2-dibromoethane
C₂H₄ + Br₂ → C₂H₄Br₂
Room temperature, no catalyst needed
C₂H₄ + Br₂ → C₂H₄Br₂
Room temperature, no catalyst needed
3. Addition of Water (Hydration)
Ethene + Water → Ethanol
C₂H₄ + H₂O → C₂H₅OH
Conditions: Phosphoric acid catalyst, 300°C, 70 atm pressure
C₂H₄ + H₂O → C₂H₅OH
Conditions: Phosphoric acid catalyst, 300°C, 70 atm pressure
Key Pattern: In ALL addition reactions, the C=C double bond breaks and becomes a C-C single bond, with new atoms adding to each carbon.