haloalkanes Flashcards
3 ways haloalkanes can be made
- alkanes - radical substitution
- alkenes - electrophilic addition
- alcohols - nucleophilic substitution
why are haloalkanes generally more reactive than alkanes
the bond strength of the C-X bond is a lot weaker than a C-H bond so require less energy to break (exception of C-F bond)
define electronegativity
the attraction between an atom and a shared pair of electrons
what is the consequence of the C-X bond
it is polar
what type of reaction is the hydrolysis of a haloalkane
a substitution reaction where the halogen is replaced by the -OH from the water
how do you produce an alcohol from a haloalkane + what conditions are needed
hydrolysis of a haloalkane is a substitution reaction in which the halogen from the haloalkane is replaced by an -OH group of water
conditions - heat under reflux
define reflux
the method used to continuously react volatile liquid whilst preventing their loss
define nucleophile
an atom or group of atoms attracted to electron deficient centre
mechanism involved in production of alcohol from haloalkane
nucleophilic substitution
what type of bond fission is involved in nucleophilic substitution
heterolytic fission
2 part reaction involved in measuring rate of hydrolysis of haloalkanes
- nucleophilic substitution of haloalkane using water as a nucleophile
- reaction between halide ion and silver ion to form silver halide
use of the ethanol in reaction measuring rate of hydrolysis of haloalkanes
both water and the haloalkane dissolve in ethanol allowing them to mix
use of the aqueous silver nitrate in reaction measuring rate of hydrolysis of haloalkanes
- provides the water as the nucleophile for hydrolysis reaction
- Ag+ ions allow to see when reaction has finished
explain difference in rate of reaction of haloalkanes
- chlorine slowest as it has the strongest bond enthalpy out of all halogens requires most energy to break
- iodine quickest as bond strength weakest so requires less energy will react easier
where is the ozone layer found
forms part of the stratosphere
what causes the photodissociation of CFCs
uv light when in stratosphere - produces Cl radicals
what does the Cl radical then do to ozone
ozone + oxygen radical –> 2x oxygen gas
Cl radical is a catalyst - isn’t used up
