Halogenoalkanes
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What is a haloalkane?
An alkane with at least one Halogen atom replacing a Hydrogen atom.
What is the general formula for a monohaloalkane?
CnH2n+1X X=halogen
Why are haloalkanes more reactive than alkanes?
They contain polar carbon-halogen bonds
Give examples of commercial uses of haloalkanes?
Fire extinguishants, refrigerants, solvents, pharmaceuticals
Why have some haloalkanes been phased out?
Some cause environmental damage such as ozone depletion such as CFCs
How are haloalkanes named?
Using IUPAC rules: longest C chain, number the chain, halogen as prefix
How are multiple halogens listed in a name?
In alphabetical order
What defines a primary haloalkane?
The halogen is attached to a carbon bonded to only one other carbon
What defines a secondary haloalkane?
The halogen is attached to a carbon bonded to two other carbons
What defines a tertiary haloalkane?
The halogen is attached to a carbon bonded to three other carbons
What is positional isomerism?
When molecules have the same molecular formula but the functional group is in different positions in the molecule.
Which type of compounds can show positional isomerism in this topic?
Haloalkanes.
Why are haloalkanes more reactive than alkanes?
Because they contain polar bonds.
Why is the Carbon-Halogen bond polar?
The halogen is more electronegative than the carbon
What charge does the carbon atom have in a haloalkane?
Partial positive charge
Why can the carbon atom be attacked by a nucleophile?
It does not have enough electrons.
What is a nucleophile?
An electron pair donor.
What does a nucleophile donate and to what?
A pair of electrons to an electron deficient atom.
Are nucleophiles always negative ions?
No e.g. NH3 is neutral but still a nucleophile
Give examples of nucleophiles that react with haloalkanes.
OH-, CN-, NH3
Why do haloalkanes undergo substitution rather than addition?
They are saturated molecules
What is nucleophilic substitution?
A reaction where a nucleophile replaces a functional group.
Which atom is replaced in haloalkane nucleophilic substitution?
The halogen atom.
What is the general equation for nucleophilic substitution of a haloalkane?
CH3CH2X + Nu- –> CH3CH2Nu +X-