Electrophilic addition mechanismsEdexcel International A Level Chemistry: Flashcards

What these 14 flashcards ask

What is an electrophile?
Where does a curly arrow start?
Why does non-polar Br₂ react with ethene?
What type of fission breaks the Br–Br bond?
What is the intermediate in the reaction of ethene with Br₂?
What is the final step in the mechanism with Br₂?
Why is H–Br polar?
Which atom in HBr is the electrophile?
Order of carbocation stability
Why are tertiary carbocations the most stable?
Major product of HBr + propene
Minor product of HBr + propene
What evidence supports a carbocation intermediate?
Name the mechanism for alkene + HBr

Exam questions on Electrophilic addition mechanisms

A student is learning how electrophiles such as bromine and hydrogen bromide react with the C=C bond of ethene, even though a bromine molecule is non-polar.
Define the term electrophile, and identify the atom in hydrogen bromide that acts as the electrophile in its reaction with ethene.2 marks
2-Methylpropene, (CH₃)₂C=CH₂, reacts with hydrogen bromide by a mechanism that involves a carbocation intermediate.
Explain why a tertiary carbocation is more stable than a primary carbocation.2 marks
Propene reacts with hydrogen bromide to give 2-bromopropane as the major product and 1-bromopropane as the minor product. Ethene also reacts with hydrogen bromide.
Explain why 2-bromopropane is the major product of the reaction of propene with hydrogen bromide.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).