hydrolysis of haloalkanes in a substitution reaction:

(i) by aqueous alkali
(ii) by water in the presence of AgNO₃ and ethanol to compare experimentally the rates of hydrolysis of different carbon–halogen bonds

PAG7

definition and use of the term nucleophile (an electron pair donor)

the mechanism of nucleophilic substitution in the hydrolysis of primary haloalkanes with aqueous alkali (see also 4.1.1h–i)

explanation of the trend in the rates of hydrolysis of primary haloalkanes in terms of the bond enthalpies of carbon–halogen bonds (C–F, C–Cl, C–Br and C–I)

production of halogen radicals by the action of ultraviolet (UV) radiation on CFCs in the upper atmosphere and the resulting catalysed breakdown of the Earth’s protective ozone layer, including equations to represent:

(i) the production of halogen radicals
(ii) the catalysed breakdown of ozone by Cl• and other radicals e.g. •NO.

Simple equations of the breakdown process are required, e.g.

CF₂Cl₂ → CF₂Cl• + •Cl
•Cl + O₃ → •ClO + O₂
•ClO + O → •Cl + O₂

Learners could be expected to construct similar equations for other stated radicals.