C15 Haloalkanes Flashcards
What are haloalkanes
Saturated organic compounds that contain C atoms and atleast 1 halogen atoms
Are haloalkanes soluble in water
Insoluble as 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 EN than C
What type of IMF’s do they have? Why?
Permanent dipole-dipole and LFs of attraction
C-X bond polarity creates permanent dipoles
When would they have higher BPs
Increase C 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 as mass of halogen > mass of H
What’s the most important factor in determining halogen reactivity
The strength of C-X bond
What would bond polarity suggest the order of reactivity would be
C-F would be most reactive as most polar bond
What would bond enthalpies suggest the order of reactivity would be
C-I would be most reactive as lowest bond enthalpy
What’s a primary halogen
Halogen atom is present at the end of the chain
Define nucleophile
Electron pair donor
Give 3 examples of nucelophiles
:OH-
:CN-
:NH3
What’s Nucleophilic substitution
A reaction where a nucleophile donates a lone pair of electrons to delta pos C atom, delta Neg atom leaves molecule (replaced by nucleophiles)
What is hydrolysis
A reaction where water is a reactant
What reactant often produces hydroxide ions for hydrolysis
Water
What fission does water undergo to produce OH-
Heterolytic fission
What are CFCs
Chlorine-fluoro-carbons - haloalkanes containing C,F and CL only (no H)
What’s the problem with CFCs
Although unreactive under normal conditions, they catalyse the breakdown of ozone in the atmosphere via free radicals substitution
What’s the main function of ozone layer
Provides protection from harmful UV radiation
Does ozone play a protection role in all layers of the atmosphere
No, in the troposphere it contributes towards photochemical smog
How do CFCs break the ozone layer down
Free radical substitution
Write an overall equation for the overall decomposition of ozone into oxygen (O2)
2O3 —> 3O2
Write free radical substitution equations to show how CL free radicals catalyse the breakdown of O3
Cl2 —> 2Cl* (in presence of UV light)
Cl* + O3 —> ClO* + O2
ClO* + O3 —> 2O2 + Cl*
Overall: 2O3 —> 3O2
