4.1.3 alkene reactions -> e- addition Flashcards
what is an electrophile
an e- pair acceptor ( usually + or partially +)
where are electrophiles attracted to
they are attracted to the pi bond as they have high e- density
draw mechanism for ethane + HBr
explain each step
search it up
- as HBr is polar as H is less electronegative than Br. So H is partially + while Br is partially -
- double bond is attracted to H causing H and Br to make a dipole
- the H-Br bond breaks heterolytically so now H joins to first C and now we have a negative Br ion (show the e-)
- the C left free is now a carbocation ( now +) so Br- now attaches to it
what is the difference between HBr and Br2
HBr is polar so it has a partially + and - end
Br2 is non-polar so it needs to be induced so it can have the polar ends (polarity is induced as the e- are moved from one side of the molecule to the other).
what is markovnikovs rule
and why?
the C which is attached to more H will gain the H from the H halide
while the one with less direct H groups and more general groups will gain the halide from the H halide
The C joint to more C’s is more stable and that one will gain the H
what is a primary, secondary and tertiary carbocation
primary -> that C is attached only to one more C
secondary -> the C is attached to 2 C
tertiary -> the C is attached to 3 more C
when is a major or minor product made
major -> when H attaches to most stable C
minor -> when H attaches to less stable C
how do u form an alchol from an alkene
- as the acid catalyst is strong it will cause the alkene to give a proton ( H+)
- the H2O will pick it up
- the water comes to the alkene and breaks the double bonds as the C with more priority will gain an H from the H3O so now h2o
- but now we have a carbo cation and the h2o all attaches to it
- but another water will come and take the spare H on h2o so now its and -oh group
https://www.khanacademy.org/science/organic-chemistry/alkenes-alkynes/alkene-reactions-tutorial/v/hydration
