haloalkanes

Question 1

define nucleophile

Answer 1

electron pair donor

Question 2

hydrolysis of haloalkanes

Answer 2

haloalkane + nucleophile (e.g. H2O or OH-) —> alcohol + halide ion

Question 3

hydrolysis and carbon-halogen bond strength

Answer 3

C-F bond strongest (unreactive), C-I bond weakest. rate increases as bonds get weaker (lower bond enthalpy) as less energy required to overcome

Question 4

why do we add ethanol when hydrolysing haloalkanes with water?

Answer 4

ethanol allows water and the haloalkane to mix and produce a single layer solution rather than two layers

Question 5

how do CFCs deplete the ozone layer?

Answer 5

UV radiation in the stratosphere provides enough energy to break the carbon-halogen bond in CFCs by homolytic fission, forming chlorine radicals. chlorine radicals can react with an ozone molecule, breaking it into oxygen.

Question 6

equation for CFC breakdown of ozone layer

Answer 6

p1 Cl. + O3 —> ClO. + O2
p2 ClO. + O —> Cl. + O2
overall O3 + O —> 2O2

Question 7

equation for nitrogen oxide breakdown of ozone

Answer 7

p1 NO. + O3 —> NO2. + O2
p2 NO2. + O —> NO. + O2
overall O3 + O —> 2O2

Question 8

equation for formation of ozone

Answer 8

initial O2 —> 2O (UV breaks oxygen into oxygen radicals)
equation O2 + O <—> O3