halogenoalkanes (organic) Flashcards
are halogenoalkanes soluble in water?
C-H bonds are non-polar so they are insoluble
do halogenoalkanes have a polar bond? why?
yes they are polar because halogens have a higher electronegativity than carbon
intermolecular forces in halogenoalkanes? why?
permanent dipole-dipole and van der Waals forces of attraction because C-X bond polarity creates permanent dipoles
When do halogenoalkanes boiling points increase
carbon chain length increases, halogen is further down group 7
what is the most important factor in determining their reactivity
carbon-halogen bond enthalpy
what is the order of reactivity of halogenoalkanes
bond enthalpy of C-X decreases down the group, so reactivity increases down the group
what is a nucleophile
a negatively charged ion/ atom with a lone pair of electrons which can be donated to an electron deficient atom
3 examples of nucleophiles
:OH-
:CN-
:NH3
what is nucleophilic substitution
a reaction where a nucleophile donates a lone pair of electrons to a delta+ C atom. delta- atom leaves molecule
what are CFCs
chlorine-fluro-carbons - haloalkanes containing C, F and Cl only (no H)
whats the problem with CFCs
although reactive under normal conditions, they catalyse the breakdown of ozone in the atmosphere via free radical substitution
What are CFCs being replaced with?
HCFCs (hydrogen, chlorine, fluorine, carbon)
HFCS (hydrogen, fluorine, carbon)
conditions/reactants needed for the elimination reaction of halogenoalkanes
NaOH or KOH dissolved in ethanol (no water)
heated
what is formed in an elimination reaction of haloalkanes
alkene, water and halogen ion
