6.31 - Halogenoalkanes and hydrolysis reactions Flashcards
What are halogenoalkanes?
A homologous series, with general formula CnH2n+1X
In terms of alkanes, what are they?
Alkanes that have had one or more hydrogen atoms replaced by halogen atoms
How else can halogenoalkanes be written?
In the form RX, where R is any alkyl group, and X is the halogen
How are halogenoalkanes named?
Number = Lowest number carbon where halogen is
Expression for the halogen
Longest length chain
What happens if there are two or more halogens?
Their prefixes appear in alphabetical order
How are halogenoalkanes classified?
As primary, secondary, or tertiary halogenoalkanes, depending on the number of alkyl groups bonded to the carbon, that is in turn bonded to the halogen
What is a primary halogenoalkane?
One with 1 alkyl group bonded to the carbon that is bonded to the halogen
What is a secondary halogenoalkane?
One with 2 alkyl groups bonded to the carbon that is bonded to the halogen
What is a tertiary halogenoalkane?
One with 3 alkyl groups bonded to the carbon that is bonded to the halogen
What makes halogenoalkanes reactive?
The polarity of the C-X bond
Why is the C-X bond polar?
- The halogen has an electronegativity higher than that of carbon
- So the halogen has a slight negative charge
- And the carbon has a slight positive charge
- Making the bond polar
What is the trend for electronegativity of halogens down the group?
As you go down the group, the electronegativity decreases
What does this mean for the polarity of the bond?
A lower electronegativity of the halogen means that the bond becomes less polar
What does the electron-defficient carbon atom attract?
Nucleophiles
What are nucleophiles?
Species that donate a lone pair of electrons to an electron-defficient atom, in order to form a covalent bond
