What you’ll learn7 learning objectivesChoose one objective for a focused lesson, or study the complete topic.15.1.1Preparation of halogenoalkanes• Recall preparation of halogenoalkanes- (a) the free-radical substitution of alkanes by Cl 2 or Br2 with ultraviolet light, as exemplified by the reactions of ethane- (b) electrophilic addition of an alkene with a halogen, X 2, or hydrogen halide, HX(g), at room temp.- (c) substitution of an alcohol, e.g. by reaction with HX(g); or with KCl and conc. H2SO4 or conc. H3PO4; or with PCl 3 and heat; or with PCl5; or with SOCl 2Syllabus objective15.1.2Classify halogenoalkanes into primary,• Classify halogenoalkanes into primary, secondary and tertiarySyllabus objective15.1.3Nucleophilic substitution• Describe the following nucleophilic substitution reactions:- (a) the reaction with NaOH(aq) and heat to produce an alcohol- (b) the reaction with KCN in ethanol and heat to produce a nitrile- (c) the reaction with NH3 in ethanol heated under pressure to produce an amine- (d) the reaction with aq. silver nitrate in ethanol as a method of identifying the halogen present as exemplified by bromoethaneSyllabus objective15.1.4Elimination reaction with NaOH in ethanol• Describe the elimination reaction with NaOH in ethanol and heat to produce an alkene as exemplified by bromoethaneSyllabus objective15.1.5SN1/SN2 substitution mechanisms• Describe the SN1 and SN2 mechanisms of nucleophilic substitution in halogenoalkanes including the inductive effects of alkyl groupsSyllabus objective15.1.6SN2/SN1 trends in halogenoalkanes• Recall that primary halogenoalkanes tend to react via the SN2 mechanism; tertiary halogenoalkanes via the SN1 mechanism; and secondary halogenoalkanes by a mixture of the two, depending on structureSyllabus objective15.1.7Rate of hydrolysis of halogenoalkanes• Describe/explain: the different reactivities of halogenoalkanes (with particular reference to the relative strengths of the C–X bonds as exemplified by the reactions of halogenoalkanes with aq. silver nitrates)Syllabus objective