CH13 Halogenoalkanes Flashcards
Are halogenoalkanes soluble in water
Insoluble as C-H bonds are non-polar, not compensated for enough by bond polarity of C-X
Do halogenoalkanes have a polar bond - why
Yes - Halogen has a higher electronegativity than C
Which intermolecular forces do they have - why
Permanent dipole-dipole and van der Waals forces of attraction - C-X bond polarity creates these dipoles
When would they have higher boiling points
Increase in carbon chain length
Halogen further down group 7
Mass of halogenoalkane vs mass of alkane of same chain length
Greater as mass of halogen > mass of H
Most important factor in determining their reactivity
C-X bond enthalpy
Order of reactivity of halogenoalkanes
Reactivity increases down the group as bond enthalpy of C-X decreases down group
What is a nucleophile
A (partially) negatively charged ion or atom with a lone pair of electrons which can be donated to an electron deficient atom
3 nucleophile examples
:OH-
:CN-
:NH3
What is nucleophilic substitution
A reaction where a nucleophile donates a lone pair of electrons to a delta positive C atom, the delta negative atom is replaced by the nucleophile
What are CFCs
Chloro-fluoro-carbons - halogenoalkanes containing only C,F and Cl
Problem with CFCs
Catalyse the breakdown of ozone in the atmosphere via free radical substitution
What are CFCs being replaced with
HCFCs and HFCs
Conditions/reactants needed for elimination of halogenoalkanes
NaOH or KOH dissolved in ethanol
Heat
What is formed in the elimination reaction of halogenoalkanes
Alkene
Water
Halogen ion
