DF - organic mechanisms

Question 1

addition

Answer 1

double bonds of alkenes can open up and other stuff (molecules or atoms) can be added

Question 2

electrophile

Answer 2

electron pair acceptors
attracted to areas where there is lots of electrons

eg. positively charged ions, H+, NO2+
eg. polar molecules, the slightly +ve atom

Question 3

electrophilic addition

Answer 3

the double bond opens up and atoms are added to the carbon atom
1. electrophilic addition happens because the double bond is has got plenty of electrons and is easily attacked by electrophiles

Question 4

carbocation

Answer 4

an organic ion containing a +vely charged carbon atom

its and intermediate

Question 5

mechanism of electrophilic addition (hydrogen halides and alkenes)

Answer 5

DRAW THIS

1. the double bond repels the electrons in HBr, polarising H-Br
2. heterolytic fission of HBr. The H (the +ve one) gives up the bonding electrons to the Br and sticks to the carbon atom
3. get a +vely charged carbonation intermediate, the Br- now zooms over…
4. …and bonds with the other C atom.

Forms: 1-bromoethane (bromoalkanes)

Question 6

mechanism of electrophilic addition (between alkene and bromine)

Answer 6

DRAW THIS

1. the double bond repels the electrons in Br2, polarising Br-Br
2. heterolytic fission of Br2. The closer Br (the +ve one) gives up the bonding electrons to the other Br and sticks to the carbon atom
3. get a +vely charged carbonation intermediate, the Br- now zooms over…
4. …and bonds with the other C atom.

Forms: 1,2-dibromoethane

Question 7

how can you confirm the model of the mechanism