Image's source: chemhelper
This mechanism takes place in alkenes.
Instructions: Follow the links (underlined sentences) below to understand the electrophilic addition mechanism.
2. The reaction with bromine... (Addition of bromine to a carbon-carbon double bond).
i. Explanation 1
ii Explanation 2
ii. 2D animation (ethene and bromine)
iv. Reaction of unsymmetrical alkene with bromine (please refer to 3 (ii)(d)) below.
v. Comparison of addition in ethene and propene (primary and secondary carbocations).
vi. Formation of 2-bromoethanol from ethene and bromine water.
3. The reaction with hydrogen halide... (Addition of hydrogen bromide)
ii. Reaction of unsymmetrical alkene (Markovnikov addition)
Eg.: The reaction between propene and hydrogen bromide in the gas phase:
CH3CH=CH2 + HBr → CH3CH2BrCH3
ii(a). Carbocations (carbonium ions) and their stability... (Essential pre-reading before you tackle anything else in this section.)
ii(b). Why unsymmetric alkenes are a problem ... (Explains the reasons behind Markovnikov's Rule, and gives a general mechanism for these more awkward reactions. This is also essential reading before you look at specific reactions.)
4. Electrophilic addition: audio tutorial
How and why are bromine molecules attracted to ethene? Jenny Wells explains to help you understand the mechanism of electrophilic addition. Download the audio file on the link above.
Download the script here Electrophilic Addition Audio Tutorial Script
5. Movie on the mechanism (if you can't see the movie here, try click at the movie file below.)
Size : 0.583 Kb
Type : mov
Organic Chemistry HX to Alkene Reaction.flv
Size : 4.819 Kb
Type : flv