3.3.3 halogenoalkanes Flashcards
define nucleophile
electron pair donors
give examples of nucleophiles
OH-
CN-
NH3
when using the nucleophile OH- what is the reagent and conditions?
reagent : potassium hydroxide
conditions : warm aqueous solvent
what is the overall equation when using OH- ions?
halogenoalkane + potassium hydroxide — alcohol + potassium halide
when using the nucleophile CN-, what is the reagent and conditions?
reagent : potassium cyanide
conditions: ethanol solvent
what is the overall equation when using CN- ions?
halogenoalkane + potassium cyanide — nitrile + potassium halide
when using the NH3 nucleophile, what is the reagent and conditions?
reagent: NH3
conditions: excess ammonia in a warm ethanol solvent in a sealed tube
what is the overall equation when using NH3?
halogenoalkane + ammonia — amine + ammonium halide
when the conditions of a reaction using OH- ions change from aqueous solvent to ethanolic solvent, what is the new name for the reaction?
an elimination reaction
in an elimination reaction what is the role of the hydroxide ion?
a base
what are the products of an elimination reaction?
alkenes, water and a halide salt
what is ozone?
it reduces the amount of harmful UV radiation reaching the earths surface by absorbing it in the atmosphere
how is ozone broken down?
by chemicals calls CFCs (chlorofluorocarbons)
they have low reactivity and are an,w to the reach the upper atmosphere unchanged
outline a mechanisms by which trichlorofluoromethane catalyses the breakdown of ozone
free radical substitution
what is the overall equation for the breakdown of ozone p?
2O3 — 3O2
outline the initiation step for the breakdown of ozone using tetrachlorofluoromethane
CFCl3 — .Cl + .CFCl2
outline the propagation steps for the breakdown of ozone using tetrachlorofluoromethane
.Cl + O3 — O2 + ClO.
ClO. + O3 — 2O2 + .Cl
