Halogenoalkanes (OG) Flashcards
Are halogenoalkanes soluble in water?
Insoluble, because C-H bonds are non-polar , not compensated for enough by C-X bond polarity
Do halogenoalkanes have a polar bond? Why?
Yes polar, as halogen has a higher electronegativity than C (Halogen is slightly negative and carbon is slightly positive)
Which intermolecular forces do they have? Why?
Permanent dipole dipole and van der waals forces of attraction
C-X bond polarity creates permanent dipoles
When would they 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 ?
It would be greater as mass of halogen is greater than mass of hydrogen
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 bond, the bond enthalpy of C-X decreases down the group, so reactivity increases down the group
What is a nucleophile?
A negatively charged ion/slightly negative atom with a lone pair of electrons which can be donated to an electron deficient atom
Give 3 examples of nucleophiles
OH-
CN-
NH3
“-“ is minus
What is nucleophilic substitution?
A reaction where a nucleophile donates a lone pair of electrons to a slightly positive carbon atom and the slightly negative atom leaves molecule and is replaced by nucleophile
Draw the mechanism for the reaction of bromoethane with NaOH (aq)
See slide 23
Draw the mechanism for the reaction of bromoethane with KCN
See slide 25
Draw the mechanism for the reaction of bromoethane with NH3
Slide 27
Draw a mechanism for the reaction of bromoethane with NaOH in ethanol
Check slide 29
What are CFCs?
Chlorine-fluoro-carbon’s-haloalkanes containing C,F and Cl only (no H)
