Revision NotesExam QuestionsPast Papers
ASChemistryCIERevision Notes3. Organic Chemistry3.3 Halogen Compounds3.3.3 Elimination Reactions of Halogenoalkanes

Elimination Reactions of Halogenoalkanes (CIE AS Chemistry)

Revision Note

Francesca

Author

Francesca

Last updated

Halogenoalkanes: Elimination Reactions

  • In an elimination reaction, an organic molecule loses a small molecule
    • In the case of halogenoalkanes this small molecule is a hydrogen halide (eg. HCl)

  • The halogenoalkanes are heated with ethanolic sodium hydroxide causing the C-X bond to break heterolytically, forming an X- ion and leaving an alkene as an organic product
    • For example, bromoethane reacts with ethanolic sodium hydroxide when heated to form ethene

 Halogen Compounds Elimination, downloadable AS & A Level Chemistry revision notes

Hydrogen bromide is eliminated to form ethene

Examiner Tip

The reaction conditions in a reaction are extremely important.If NaOH(ethanol) is used, an elimination reaction takes place to form an alkene from a halogenoalkane.If NaOH(aq) is used, a nucleophilic substitution reaction takes place to form an alcohol from a halogenoalkane.

You've read 0 of your 5 free revision notes this week

Sign up now. It’s free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

    Test yourself

    Did this page help you?

    Previous:3.3.2 Substitution Reactions of HalogenoalkanesNext:3.3.4 SN1 & SN2
    Francesca

    Author: Francesca

    Expertise: Head of Science

    Fran studied for a BSc in Chemistry with Forensic Science, and since graduating taught A level Chemistry in the UK for over 11 years. She studied for an MBA in Senior Leadership, and has held a number of roles during her time in Education, including Head of Chemistry, Head of Science and most recently as an Assistant Headteacher. In this role, she used her passion for education to drive improvement and success for staff and students across a number of subjects in addition to Science, supporting them to achieve their full potential. Fran has co-written Science textbooks, delivered CPD for teachers, and worked as an examiner for a number of UK exam boards.