• Describe the structure, general formula and uses of halogenoalkanes.

• Describe and explain the nature of the carbon–halogen bond and its susceptibility to nucleophilic attack.

• Define the term nucleophile as an electron pair donor.

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3-bromo-2-chloropentane

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Polarity of the carbon-halogen bond

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Polarity of the carbon-halogen bond decreases down the group

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• Describe the hydrolysis of halogenoalkanes as a nucleophilic substitution reaction.

• Describe the mechanism of nucleophilic substitution in the hydrolysis of primary halogenoalkanes with hot aqueous alkali.

• Explain the rates of primary halogenoalkane hydrolysis in terms of the relative bond enthalpies of carbon–halogen bonds.

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Mechanism for nucleophilic substitution

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Curly arrows are used to represent the movement of electron pairs

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Rates of hydrolysis of halogenoalkanes

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• Outline the uses of chloroethene and tetrafluoroethene in the production of the plastics PVC and PTFE.

• Explain why CFCs were first developed and their subsequent effect on the ozone layer.

• Outline the role of ‘green’ chemistry in minimising damage to the environment by promoting alternatives to CFCs.

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The polymerisation of tetrafluoroethene produces PTFE or Teflon

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The polymerisation of chloroethene to produce PVC

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R-22 (CHCIF2) – the main HCFC used today as a refrigerant

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