Halogenoalkanes Flashcards
are halogenoalkanes soluble in water
insoluble as C-H bonds are nonpolar not compensated for enough by C-X bond polarity
do halogenoalkanes have a polar bonds and why
yes there is a polar bond as halogen has a higher electronegativity than C
which intermolecular forces do they have and why
permanent dipole-dipole and van der Waals forces of attraction
the C-X bond polarity creates permanent dipoles
when would halogenoalkanes have higher boiling points
increase carbon chain length
halogen further down group 7
how would the mass of a haloalkane compare with the mass of an alkane of the same chain length
greater mass as the mass of halogen is bigger than H
what is the most important factor in determining their reactivity
carbon halogen bond enthalpy
what is the order of reactivity of halogenoalkanes
although C-F is the most polar bon and the bond enthalpy decreases down the group so reactivity increases down the group
define a nucleophile
a negatively charged ion or atom with a lone pair of electrons which can be donated to an electron deficient atom
give three examples of nucleophiles
:OH-
:CN-
:NH3-
what is nucleophilic substitution
a reaction where a nucleophile donates a lone pair of electrons to a delta plus C and the delta negative atom leaves the molecule
draw the mechanism for the reaction of bromoethane with NaOH
CH3CH2Br + OH —> CH3CH2OH
what are CFCs
chloro-fluoro carbons that are halogenoalkanes containing C,F and Cl only
what is the problem with CFCs
although unreactive under normal conditions they catalyse the breakdown of ozone in the atmosphere via free radical sub
what are CFCs being replaces with
hydrogen, chlorine, fluorine, carbon
hydrogen, fluorine, carbon
what are the conditions and reactants needed for the elimination reactions for halogenoalkanes
NaOH or KOH dissolved in ethanol, heated
what is formed in the elimination reactions of halogenoalkanes
alkene, water and halogen ion
