mechanisms Flashcards
What is the reaction called between a halogen and an alkane?
Free radical substitution
What happens in an 1st step in free radical substitution and its name?
Initiation:
The 2 halogens have UV light beamed at them so they become 2 radicals
UV. .
X2 —–> 2X
What happens in an 2nd step in free radical substitution and its name?
Propagation:
1 of the halogen radicals reacts the alkane to form a stable halogen but a radical alkane because the halogen takes off a hydrogen.
Or one of the radical alkanes could react with the halogen to form a stable alkane and a radical halogen
What happens in an 3rd step in free radical substitution and its name?
Termination:
The radicals come together and stop the reaction
.
2X -----> X2
.
2alkane ----> alkane
. . alkane + X ---> halo - alkane
What is combustion?
The complete reaction of an alkane and oxygen
What is the formula for complete combustion?
Alkane + O2 —-> CO2 and H2O
What is the formula for incomplete combustion to make C?
Alkane + O —-> CO + H20
What is the formula for incomplete combustion to make CO?
Alkane + O —-> C + H20
What is the name of a reaction between an alkene and a hydrogen halide?
Electrophilic addition
What is the mechanism for electrophilic addition with an alkene and a hydrogen halide?
-The hydrogen halide will be a dipole with the H as positive region and the halogen as a negative region
On one of the carbons in the C=C will lose an electron to the H and the H will give an electron to the halogen
-The H will join to the C and open up the C=C bond and one of the C ‘s will be a radical with 1 less electron and the bromine will have 1 extra so they react to form a halo - alkane
What is hydrogenation?
When hydrogen is added to an alkene to make an alkane
What is hydration?
When steam is added to an alkene to make an alcohol
What is Markovnikoff’s rule?
The radical carbon will be the one attached to the most other carbons
What is a primary position with Markovnikoff’s rule?
The radical carbon has 1 other carbon attached to it
What is a secondary position with Markovnikoff’s rule?
The radical carbon has 2 other carbons attached to it
